Impact of Non-Diameter Aortic Indices on Surgical Eligibility: Results from the TITAN: SvS Randomized Controlled Trial

OBJECTIVES

Traditional criteria for intervention on an asymptomatic ascending aortic aneurysm has been a maximal aortic diameter of ⩾5.5cm. The 2022 ACC/AHA aortic guidelines adopted cross-sectional aortic area/height ratio, aortic size index (ASI) and aortic height index (AHI) as alternate parameters for surgical intervention. The objective of this study was to evaluate the impact of using these newer indices on patient eligibility for surgical intervention in a prospective, multicenter cohort with moderate sized ascending aortic aneurysms between 5.0-5.4 cm.

METHODS

Patients enrolled from 2018 to 2023 in the randomization or registry arms of the multicenter trial, TITAN: SvS, were included in the study. Clinical data was captured prospectively in an online database. Imaging data were derived from a core CT lab.

RESULTS

Among the 329 included patients, 20% were female. Mean age was 65.0 ± 11.6 years and mean maximal aortic diameter was 50.8 ±3.9 mm. In the one third of all patients (n=109) who met any one of the three criteria (i.e., ASI ⩾ 3.08 cm/m2, AHI ⩾ 3.21 cm/m or cross-sectional aortic area/height ⩾ 10 cm2/m), their mean maximal aortic diameter was 52.5 ±0.52 mm. Alternate criteria were most commonly met in females compared to males: 20% versus 2% for ASI (p<0.001), 39% versus 5% for AHI (p<0.001) and 39% versus 21% for cross-sectional aortic area/height (p=0.002), respectively.

CONCLUSIONS

One third of patients in Titan:SvS would meet criteria for surgical intervention based on novel parameters vs. the classic definition of diameter⩾5.5cm. Surgical thresholds for ASI, AHI or cross-sectional aortic area/height ratio are more likely to be met in female patients compared to male patients.

Percutaneous ventricular assist device for higher-risk percutaneous coronary intervention in surgically ineligible patients: Indications and outcomes from the OPTIMUM study

BACKGROUND

Indications and outcomes for percutaneous ventricular assist device (pVAD) use in surgically ineligible patients undergoing percutaneous coronary intervention (PCI) remain poorly characterized.

AIMS

We sought to describe the use and timing of pVAD and outcome in surgically ineligible patients.

METHODS

Among 726 patients enrolled in the prospective OPTIMUM study, clinical and health status outcomes were assessed in patients who underwent pVAD-assisted PCI and those without pVAD.

RESULTS

Compared with patients not receiving pVAD (N = 579), those treated with pVAD (N = 142) more likely had heart failure, lower left ventricular ejection fraction (30.7 ± 13.6 vs. 45.9 ± 15.5, p < 0.01), and higher STS 30-day predicted mortality (4.2 [2.1-8.0] vs. 3.3 [1.7-6.6], p = 0.01) and SYNTAX scores (36.1 ± 12.2, vs. 31.5 ± 12.1, p < 0.01). While the pVAD group had higher in-hospital (5.6% vs. 2.2%, p = 0.046), 30-day (9.0% vs. 4.0%, p = 0.01) and 6-month (20.4% vs. 11.7%, p < 0.01) mortality compared to patients without pVAD, this difference appeared to be largely driven by significantly higher mortality among the 20 (14%) patients with unplanned pVAD use (30% in-hospital mortality with unplanned PVAD vs. 1.6% with planned, p < 0.01; 30-day mortality, 38.1% vs. 4.5%, p < 0.01). The degree of 6-month health status improvement among survivors was similar between groups.

CONCLUSION

Surgically ineligible patients with pVAD-assisted PCI had more complex baseline characteristics compared with those without pVAD. Higher mortality in the pVAD group appeared to be driven by very poor outcomes by patients with unplanned, rescue pVAD.

Outcomes of double-valve surgery for infective endocarditis are improving in the modern era

BACKGROUND

The incidence of infective endocarditis (IE) is rapidly increasing. Contemporary outcomes following high-risk double valve surgery (DVS) for IE are not well described.

METHODS

Between 2001 and 2021, 211 patients with IE underwent combined aortic and mitral valve surgery at a tertiary care referral center. Data from the Society of Thoracic Surgeons registry, including demographics, operative details, and outcomes, were collected. Risk factors for 30-day and 1-year-mortality were analyzed. Survival was analyzed using Kaplan-Meier and Cox proportional hazards modeling.

RESULTS

The study cohort had a male preponderance (73%), with a median age of 56 years (interquartile range [IQR], 44 to 63 years). Forty-five patients (21%) had a history of intravenous (IV) drug abuse, 50 (24%) were on preoperative dialysis, and 50 (24%) had prosthetic valve endocarditis. Thirty-day and 1-year mortality were 14% (n = 30) and 30% (n = 61), respectively. On multivariable Cox regression adjusting for age, prosthetic valve endocarditis, postoperative intra-aortic balloon pump (IABP), history of dialysis (adjusted hazard ratio [aHR], 1.9; 95% confidence interval [CI], 1.3 to 2.9; P = .002) and IV drug abuse (aHR, 2.0; 95% CI, 1.1-3.5; P = .02) were predictive of decreased survival. Undergoing surgery after 2010 was predictive of improved survival (aHR, 0.5; 95% CI, 0.3 to 0.8; P = .006). These patients were more likely to undergo urgent/emergent surgery (83% vs 29%; P < .001) and less likely to have an aortic root abscess (40% vs 58%; P = .03) or to require the commando procedure (13% vs 33%; P = .002).

CONCLUSIONS

In this large series evaluating outcomes of DVS for IE in the modern era, although the mortality risk remained elevated, improving outcomes may be associated with earlier surgical intervention before significant disease progression. Multidisciplinary evaluation for complex IE may be considered to better understand the optimal timing and repair strategy.

Outcomes of Medical Therapy Plus PCI for Multivessel or Left Main CAD Ineligible for Surgery

BACKGROUND

Percutaneous coronary intervention (PCI) is increasingly used to revascularize patients ineligible for CABG, but few studies describe these patients and their outcomes.

OBJECTIVES

This study sought to describe characteristics, utility of risk prediction, and outcomes of patients with left main or multivessel coronary artery disease ineligible for coronary bypass grafting (CABG).

METHODS

Patients with complex coronary artery disease ineligible for CABG were enrolled in a prospective registry of medical therapy + PCI. Angiograms were evaluated by an independent core laboratory. Observed-to-expected 30-day mortality ratios were calculated using The Society for Thoracic Surgeons (STS) and EuroSCORE (European System for Cardiac Operative Risk Evaluation) II scores, surgeon-estimated 30-day mortality, and the National Cardiovascular Data Registry (NCDR) CathPCI model. Health status was assessed at baseline, 1 month, and 6 months.

RESULTS

A total of 726 patients were enrolled from 22 programs. The mean SYNTAX (Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery) score was 32.4 ± 12.2 before and 15.0 ± 11.7 after PCI. All-cause mortality was 5.6% at 30 days and 12.3% at 6 months. Observed-to-expected mortality ratios were 1.06 (95% CI: 0.71-1.36) with The Society for Thoracic Surgeons score, 0.99 (95% CI: 0.71-1.27) with the EuroSCORE II, 0.59 (95% CI: 0.42-0.77) using cardiac surgeons' estimates, and 4.46 (95% CI: 2.35-7.99) using the NCDR CathPCI score. Health status improved significantly from baseline to 6 months: SAQ summary score (65.9 ± 22.5 vs 86.5 ± 15.1; P < 0.0001), Kansas City Cardiomyopathy Questionnaire summary score (54.1 ± 27.2 vs 82.6 ± 19.7; P < 0.0001).

CONCLUSIONS

Patients ineligible for CABG who undergo PCI have complex clinical profiles and high disease burden. Following PCI, short-term mortality is considerably lower than surgeons' estimates, similar to surgical risk model predictions but is over 4-fold higher than estimated by the NCDR CathPCI model. Patients' health status improved significantly through 6 months.

Survival after operative repair of acute type A aortic dissection varies according to the presence and type of preoperative malperfusion

OBJECTIVE

Approximately one-quarter of patients with acute type A aortic dissection (TAAD) present with concomitant malperfusion of coronary arteries, mesenteric circulation, lower extremities, kidneys, brain, and/or coma. It is generally accepted that TAAD patients who present with malperfusion experience higher mortality rates than patients without, although how specific malperfusion syndromes, alone or in combination, affect mortality is not well described.

METHODS

The International Registry of Acute Aortic Dissection database was queried for patients who underwent surgical repair of TAAD. Patients were stratified according to the presence/absence of malperfusion at presentation. Multivariable logistic regression was used to evaluate in-hospital mortality according to malperfusion type. Kaplan-Meier estimates were used to estimate 30-day postoperative survival.

RESULTS

Six thousand four hundred thirty-seven patients underwent surgical repair of acute TAAD, of whom 2642 (41%) had 1 or more preoperative malperfusion syndromes. Mesenteric malperfusion (adjusted odds ratio [AOR], 4.84; P < .001) was associated with the highest odds of in-hospital mortality, followed by coma (AOR, 1.88; P = .007), limb ischemia (AOR, 1.73; P = .008), and coronary malperfusion (AOR, 1.51; P = .02). Renal malperfusion (AOR, 1.37; P = .24) and neurologic deficit (AOR, 1.35; P = .28) were not associated with increased in-hospital mortality. In patients who survived to discharge, there was no difference in 1-year postdischarge survival in the malperfusion and no malperfusion cohorts (P = .36).

CONCLUSIONS

Survival during the index admission after TAAD repair varies according to the presence and type of malperfusion syndromes, with mesenteric malperfusion being associated with the highest odds of in-hospital death. Not only the presence of malperfusion but rather specific malperfusion syndromes should be considered when assessing a patient's risk of undergoing TAAD repair.

Association of STS database variables with repair durability in ischemic mitral regurgitation using machine learning

BACKGROUND

Machine learning (ML) can identify nonintuitive clinical variable combinations that predict clinical outcomes. To assess the potential predictive contribution of standardized Society of Thoracic Surgeons (STS) Database clinical variables, we used ML to detect their association with repair durability in ischemic mitral regurgitation (IMR) patients in a single institution study.

METHODS

STS Database variables (n = 53) served as predictors of repair durability in ML modeling of 224 patients who underwent surgical revascularization and mitral valve repair for IMR. Follow-up mortality and echocardiography data allowed 1-year outcome analysis in 173 patients. Supervised ML analyses were performed using recurrence (≥3+ IMR) or death versus nonrecurrence (<3+ IMR) as the binary outcome classification.

RESULTS

We tested standard ML and deep learning algorithms, including support vector machines, logistic regression, and deep neural networks. Following training, final models were utilized to predict class labels for the patients in the test set, producing receiver operating characteristic (ROC) curves. The three models produced similar area under the curve (AUC), and predicted class labels with promising accuracy (AUC = 0.72-0.75).

CONCLUSIONS

Readily-available STS Database variables have potential to play a significant role in the development of ML models to direct durable surgical therapy in IMR patients.

SVEP1 is a human coronary artery disease locus that promotes atherosclerosis

A low-frequency variant of sushi, von Willebrand factor type A, EGF, and pentraxin domain-containing protein 1 (SVEP1), an extracellular matrix protein, is associated with risk of coronary disease in humans independent of plasma lipids. Despite a robust statistical association, if and how SVEP1 might contribute to atherosclerosis remained unclear. Here, using Mendelian randomization and complementary mouse models, we provide evidence that SVEP1 promotes atherosclerosis in humans and mice and is expressed by vascular smooth muscle cells (VSMCs) within the atherosclerotic plaque. VSMCs also interact with SVEP1, causing proliferation and dysregulation of key differentiation pathways, including integrin and Notch signaling. Fibroblast growth factor receptor transcription increases in VSMCs interacting with SVEP1 and is further increased by the coronary disease-associated SVEP1 variant p.D2702G. These effects ultimately drive inflammation and promote atherosclerosis. Together, our results suggest that VSMC-derived SVEP1 is a proatherogenic factor and support the concept that pharmacological inhibition of SVEP1 should protect against atherosclerosis in humans.

Impact of Surgical Experience on Operative Mortality After Reoperative Cardiac Surgery

BACKGROUND

Learning curves and skill attrition with aging have been reported to impair outcomes in select surgical subspecialties, but their role in complex cardiac surgery remains unknown.

METHODS

From 1986 to 2019, 2314 patients underwent reoperative cardiac surgery: coronary artery bypass grafting (n = 543), valve (n = 1527), or combined coronary artery bypass grafting and valve (n = 244). Thirty-four different surgeons in practice between 1 and 39 years were included. Standardized mortality ratio (observed-to-expected) was determined for all surgeons in each post-training year of experience.

RESULTS

Risk-adjusted cumulative sum change-point analysis was used to define five distinct career phases: 0 to 4 years, 5 to 8 years, 9 to 17 years, 18 to 28 years, and 29 to 39 years. With 5 to 8 years and 18 to 28 years of experience, standardized mortality ratio was near unity (0.95 and 1.05, respectively) and lowest with 9 to 17 years of experience (0.78, P = .03). In the youngest experience group (0 to 4 years), observed and expected mortality were both highest, and standardized mortality ratio was elevated at 1.29, which approached statistical significance (P = .059). In the oldest experience group (29 to 39 years), expected mortality was low compared with most other groups but observed mortality increased, yielding a significantly elevated standardized mortality ratio at 1.53 (P = .032).

CONCLUSIONS

Standardized mortality ratios with reoperative cardiac surgery were highest early and late in a surgeon's career and lowest in mid career. As surgeons gain experience, outcomes improve through the first two career decades, then stabilize in the third decade before declining in the fourth decade.

Radiation Exposure During Transcatheter Valve Replacement: What Cardiac Surgeons Need to Know

BACKGROUND

Transcatheter aortic valve replacement (TAVR) and transcatheter mitral valve replacement expose operators to radiation. These procedures differ primarily in whether they are performed via a transfemoral (TF) or an alternative access (AA) approach. This study compared operator radiation exposure during transcatheter valve implantation when performed via a TF vs an AA approach, when performed in a catheterization lab vs a hybrid operating room (OR), and investigated the potential benefit of disposable shielding.

METHODS

Dosimeters were worn during TAVR-TF (n = 50) and TAVR-AA (n = 31) procedures by operators. All TAVR-AA procedures were performed in a hybrid OR and TF procedures were performed in either catheterization labs (n = 16) or a hybrid OR (n = 34). Disposable radiation shielding pads (RADPAD; Worldwide Innovations and Technologies, Inc, Kansas City) or a placebo were added in a randomized, blinded fashion.

RESULTS

Team radiation exposure was higher after TAVR-AA vs TAVR-TF (median 15.1 mRad [interquartile range: IQR 8.6, 32.4] vs 5.5 mRad [IQR 2.4, 9.8], P < .001). TAVR-TF procedures required the same amount of fluoroscopy time regardless of where they were performed (20.3 ± 7.4 min in hybrid OR vs 19.0 ± 6.4 min in catheterization lab, P = .55). However, radiation exposure for TAVR-TF remained higher when performed in a hybrid OR (median 9.0 mRad [IQR 4.5, 11.9] vs 2.2 mRad [IQR 1.3, 2.8], P < .001). Radiation exposure was greatest for TAVR-AA (median 15.1 mRad [IQR 8.6, 32.4]). The use of RADPAD did not decrease radiation exposure (median 9.0 mRad [IQR 4.5, 14.7] vs 9.4 mRad [IQR 2.8, 19.5], P = .82).

CONCLUSIONS

Procedures performed in the hybrid OR were associated with higher operator radiation exposure. In comparison with the TF approach, AA cases had the highest levels of operator radiation. This is particularly important in cases of transcatheter mitral valve replacement that can only be done via an AA approach. The use of disposable radiation shielding in this series did not attenuate operator radiation exposure. Radiation shielding within hybrid ORs should be scrutinized in an effort to remain on par with that found within catheterization labs.

GITR agonist enhances vaccination responses in lung cancer

An immune tolerant tumor microenvironment promotes immune evasion of lung cancer. Agents that antagonize immune tolerance will thus aid the fight against this devastating disease. Members of the tumor necrosis factor receptor (TNFR) family modulate the magnitude, duration and phenotype of immune responsiveness to antigens. Among these, GITR expressed on immune cells functions as a key regulator in inflammatory and immune responses. Here, we evaluate the GITR agonistic antibody (DTA-1) as a mono-therapy and in combination with therapeutic vaccination in murine lung cancer models. We found that DTA-1 treatment of tumor-bearing mice increased: (i) the frequency and activation of intratumoral natural killer (NK) cells and T lymphocytes, (ii) the antigen presenting cell (APC) activity in the tumor, and (iii) systemic T-cell specific tumor cell cytolysis. DTA-1 treatment enhanced tumor cell apoptosis as quantified by cleaved caspase-3 staining in the tumors. DTA-1 treatment increased expression of IFNγ, TNFα and IL-12 but reduced IL-10 levels in tumors. Furthermore, increased anti-angiogenic chemokines corresponding with decreased pro-angiogenic chemokine levels correlated with reduced expression of the endothelial cell marker Meca 32 in the tumors of DTA-1 treated mice. In accordance, there was reduced tumor growth (8-fold by weight) in the DTA-1 treatment group. NK cell depletion markedly inhibited the antitumor response elicited by DTA-1. DTA-1 combined with therapeutic vaccination caused tumor rejection in 38% of mice and a 20-fold reduction in tumor burden in the remaining mice relative to control. Mice that rejected tumors following therapy developed immunological memory against subsequent re-challenge. Our data demonstrates GITR agonist antibody activated NK cell and T lymphocyte activity, and enhanced therapeutic vaccination responses against lung cancer.

Combination Treatment with Apricoxib and IL-27 Enhances Inhibition of Epithelial-Mesenchymal Transition in Human Lung Cancer Cells through a STAT1 Dominant Pathway

BACKGROUND

The cyclooxygenase 2 (COX-2) pathway has been implicated in the molecular pathogenesis of many malignancies, including lung cancer. Apricoxib, a selective COX-2 inhibitor, has been described to inhibit epithelial-mesenchymal transition (EMT) in human malignancies. The mechanism by which apricoxib may alter the tumor microenvironment by affecting EMT through other important signaling pathways is poorly defined. IL-27 has been shown to have anti-tumor activity and our recent study showed that IL-27 inhibited EMT through a STAT1 dominant pathway.

OBJECTIVE

The purpose of this study is to investigate the role of apricoxib combined with IL-27 in inhibiting lung carcinogenesis by modulation of EMT through STAT signaling.

METHODS AND RESULTS

Western blot analysis revealed that IL-27 stimulation of human non-small cell lung cancer (NSCLC) cell lines results in STAT1 and STAT3 activation, decreased Snail protein and mesenchymal markers (N-cadherin and vimentin) and a concomitant increase in expression of epithelial markers (E-cadherin, β-and γ-catenins), and inhibition of cell migration. The combination of apricoxib and IL-27 resulted in augmentation of STAT1 activation. However, IL-27 mediated STAT3 activation was decreased by the addition of apricoxib. STAT1 siRNA was used to determine the involvement of STAT1 pathway in the enhanced inhibition of EMT and cell migration by the combined IL-27 and apricoxib treatment. Pretreatment of cells with STAT1 siRNA inhibited the effect of combined IL-27 and apricoxib in the activation of STAT1 and STAT3. In addition, the augmented expression of epithelial markers, decreased expression mesenchymal markers, and inhibited cell migration by the combination treatment were also inhibited by STAT1 siRNA, suggesting that the STAT1 pathway is important in the enhanced effect from the combination treatment.

CONCLUSION

Combined apricoxib and IL-27 has an enhanced effect in inhibition of epithelial-mesenchymal transition and cell migration in human lung cancer cells through a STAT1 dominant pathway.

IL-27 inhibits epithelial-mesenchymal transition and angiogenic factor production in a STAT1-dominant pathway in human non-small cell lung cancer

BACKGROUND

Interleukin-27 signaling is mediated by the JAK-STAT pathway via activation of STAT1 and STAT3, which have tumor suppressive and oncogenic activities, respectively. Epithelial-mesenchymal transition (EMT) and angiogenesis are key processes in carcinogenesis. Although IL-27 has been shown to have potent anti-tumor activity in various cancer models, the role of IL-27 in EMT and angiogenesis is poorly understood. In this study, we investigated the role of IL-27 in regulating EMT and angiogenesis through modulation of the STAT pathways in human non-small cell lung carcinoma (NSCLC) cells.

METHODS

STAT activation following IL-27 exposure was measured in human NSCLC cell lines. Expression of epithelial (E-cadherin, γ-catenin) and mesenchymal (N-cadherin, vimentin) markers were assessed by Western blot analysis. Production of pro-angiogenic factors (VEGF, IL-8/CXCL8, CXCL5) were examined by ELISA. Cell motility was examined by an in vitro scratch and transwell migration assays. Selective inhibitors of STAT1 (STAT1 siRNAs) and STAT3 (Stattic) were used to determine whether both STAT1 and STAT3 are required for IL-27 mediated inhibition of EMT and secretion of angiogenic factors.

RESULTS

Our results demonstrate that IL-27 stimulation in NSCLC resulted in 1) STAT1 and STAT3 activation in a JAK-dependent manner, 2) development of epithelial phenotypes, including a decrease in the expression of a transcriptional repressor for E-cadherin (SNAIL), and mesenchymal marker (vimentin) with a reciprocal increase in the expression of epithelial markers, 3) inhibition of cell migration, and 4) reduced production of pro-angiogenic factors. STAT1 inhibition in IL-27-treated cells reversed the IL-27 effect with resultant increased expression of Snail, vimentin and the pro-angiogenic factors. The inhibition of STAT3 activation had no effect on the development of the epithelial phenotype.

CONCLUSION

IL-27 induces mesenchymal to epithelial transition and inhibits the production of pro-angiogenic factors in a STAT1-dominant pathway. These findings highlight the importance of STAT1 in repressing lung carcinogenesis and describe a new anti-tumor mechanism of IL-27.

Abstract 2558: VEGF-dependent suppression of prostaglandin transporter (PGT) expression in Kras mutant human bronchial epithelial cells

Prostaglandin transporters are expressed in cyclooxygenase-positive cells and provide the dominant mechanisms for transport of prostaglandins (PG) across the cell membrane. Specifically, the prostaglandin transporter PGT, expressed in many cell types including lung epithelia, is responsible for the uptake of prostaglandin E2 (PGE2) for intracellular metabolism and degradation by 15-prostaglandin dehydrogenase (15-PGDH). The regulation of prostaglandin transporters has not been fully explored in lung cancer. We hypothesize that loss of PGT expression is important in lung carcinogenesis and its loss may be enhanced in the presence of common mutations in premalignant bronchial epithelial cells and non-small cell lung cancer (NSCLC). Our preliminary studies show that PGT expression (protein and mRNA) and 15-PGDH are significantly downregulated in Kras mutant human bronchial epithelial cells (HBEC) and in NSCLC. It is well known that Kras mutant cancers are associated with increased production of VEGF, an important factor in tumor angiogenesis. In HBEC, we found significantly higher VEGF levels in Kras mutants compared to vector controls (2242 versus 628 pg/mg, p = 0.04). We proposed that VEGF modulates PGT expression and tested our hypothesis by treating HBEC and NSCLC with human recombinant VEGF. PGT expression is downregulated with exogenous VEGF treatment and neutralizing VEGF production (neutralizing VEGF antibody) prevented the loss of PGT expression. The MEK1/2 inhibitor PD98059 upregulated PGT expression in HBEC Kras. Our results suggest Kras mutation is associated with loss of PGT expression and may be dependent on VEGF production. Modulation of PGT expression may be important in lung carcinogenesis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2558. doi:1538-7445.AM2012-2558

Abstract 339: Apricoxib, a selective COX-2 inhibitor, suppresses IL-27-mediated STAT3 activation and potentiates its inhibition of epithelial to mesenchymal transition in human non-small cell lung cancer

Introduction The cyclooxygenase 2 (COX-2) pathway has been implicated in the molecular pathogenesis of many cancers. Apricoxib, a selective COX-2 inhibitor, has recently been demonstrated to inhibit epithelial to mesenchymal transition (EMT) in human malignancies. EMT is a critical process in cancer progression and metastasis whereby epithelial cells undergo changes to a migratory, mesenchymal phenotype. The mechanism by which apricoxib may alter the tumor microenvironment by impacting other important pathways in EMT is poorly defined. To investigate this concept, we utilized Interleukin-27 (IL-27), a member of the IL-12 family, which signals through the JAK-STAT pathway and activates transcriptional factors with opposing roles in carcinogenesis, STAT1 (tumor suppressor) and STAT3 (oncogene). IL-27 has been shown to have anti-tumor activity, but understanding of its mechanism is limited. We previously demonstrated that IL-27 activates both STAT1 and STAT3 pathways in human non-small cell lung cancer (NSCLC) and that the balance in STAT1 and STAT3 activation is important in inhibiting EMT. Here, we studied the effect of apricoxib on IL-27-mediated STAT activation and EMT inhibition. We hypothesize that apricoxib modulates STAT1 and STAT3 activation and regulates EMT. Methods A human NSCLC cell line, A549, was pre-treated with apricoxib (80nM-10µM) for up to 24 hours prior to IL-27 stimulation (50ng/mL). Activation of STAT1 and STAT3 proteins, demonstrated by tyrosine phosphorylation, was measured by Western Blot analysis. Additionally, epithelial markers (E-cadherin, γ-catenin, β-catenin) and mesenchymal markers (N-cadherin, vimentin, snail) were evaluated also by Western blotting. Results IL-27 alone induced phosphorylation of STAT1 and STAT3 proteins compared to untreated control. Pre-treatment with apricoxib resulted in decreased levels of IL-27-mediated STAT1 and STAT3 phosphorylation compared to the IL-27 alone group. Apricoxib alone did not cause STAT1 or STAT3 activation. IL-27 treatment alone increased the levels of E-cadherin, γ-catenin, and β-catenin and decreased the levels of N-cadherin, vimentin, and snail compared to untreated control. Pre-treatment with apricoxib for 24 hours prior to IL-27 exposure resulted in potentiation of IL-27-mediated reduction of N-cadherin, vimentin, and snail and further increased the levels of E-cadherin when compared to the IL-27 alone group. There appeared to be no impact on the expression of γ-catenin or β-catenin with the addition of apricoxib to IL-27. Conclusions Apricoxib inhibits IL-27-mediated activation of STAT1 and STAT3, and potentiates the IL-27-mediated inhibition of epithelial to mesenchymal transition. These findings suggest that apricoxib may regulate EMT through modulation of the STAT pathway.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 339. doi:1538-7445.AM2012-339

Abstract 4268: Interleukin-27 inhibits angiogenesis in non-small cell lung cancer

Interleukin-27 (IL-27), the newest member of the IL-6/IL-12 family, is secreted by antigen presenting cells and has anti-tumor activity through its activation of the JAK-STAT pathway. Transcriptional factors STAT1 and STAT3 have been implicated in the balance of tumor suppressor and oncogenic functions. Angiogenesis is a critical process during carcinogenesis. We investigated the role of IL-27 in tumor angiogenesis in lung cancer. Human bronchial epithelial cells (HBECs), genetically modified HBEC to over express Snail and K-ras (HBEC-Snail, HBEC-K-ras), and human non-small cell lung cancer (NSCLC) lines (A549, H2122) were treated with IL-27 at multiple time points. Phosphorylation of STAT1 and STAT3 measured by Western Blot after IL-27 exposure demonstrated activation of both pathways in these cell lines. Protein production of an important pro-angiogenic factor, vascular endothelial growth factor (VEGF), was measured by ELISA and Western analysis. After exposure to IL-27, there was a 60-80% decrease in VEGF protein expression of VEGF by ELISA (confirmed by Western analysis in the NSCLC lines but not in the HBECs or their genetically modified derivatives). The IL-27 down regulation of VEGF was not increased by the addition of a STAT3 inhibitor. In summary, IL-27 inhibits VEGF production in NSCLC through a mechanism independent of STAT3, suggesting that STAT1 may play a dominant role in IL-27 mediated angiogenesis suppression.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4268. doi:10.1158/1538-7445.AM2011-4268

Abstract 3425: Interleukin-27 inhibits epithelial mesenchymal transition in lung carcinogenesis

Interleukin-27 (IL-27), the newest member of the IL-6/IL-12 family, is secreted by antigen presenting cells and has anti-tumor activity through its activation of the JAK-STAT pathway. Transcriptional factors STAT1 and STAT3 have been implicated in the balance of tumor suppressor and oncogenic functions. Epithelial mesenchymal transition (EMT) is a process whereby cells undergo changes from a highly polarized epithelial phenotype to a mesenchymal, migratory phenotype, which plays an important role in tumor metastasis. The role of IL-27 in EMT was evaluated in lung carcinogenesis. Human bronchial epithelial cells (HBECs), genetically modified HBEC to over-express Snail and K-ras (HBEC-Snail, HBEC-K-ras), and non-small cell lung cancer (NSCLC) lines (A549, H2122) were treated with IL-27 at multiple time points. Phosphorylation of STAT1 and STAT3 measured by Western Blot demonstrated activation of both pathways in these cell lines treated with IL-27. However, the STAT1 pathway was attenuated in HBEC-K-ras cells exposed to IL-27. Western analysis of markers for epithelial to mesenchymal transition (EMT) (E-cadherin, γ-catenin, N-cadherin, Vimentin, and Snail) showed up-regulation of E-cadherin and γ-catenin, important for the epithelial phenotype, which peaked 8 hours after IL-27 exposure, while markers important for the mesenchymal phenotype (N-cadherin, Vimentin, and Snail) were all down-regulated at similar time points. The addition of a STAT3 inhibitor to IL-27 treatment led to continued down-regulation of Vimentin beyond 8 hours. A wound healing functional assay to study cell migration after IL-27 treatment of cancer cell lines for up to 48 hours, demonstrated overall decrease in cell migration. In summary, IL-27 inhibits epithelial mesenchymal transition in NSCLCs and oncogenically manipulated HBECs through the regulation of STAT1 and STAT3 pathways.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3425. doi:10.1158/1538-7445.AM2011-3425

Ossicular motion related to middle ear transmission delay in gerbil

The middle ear transmits sound efficiently from the air in the ear canal (EC) to the fluid filled cochlea. In gerbil, middle ear transmission produces a constant pressure gain between the EC and the cochlea of ∼25 dB from 2 to 40 kHz, and a delay-like phase corresponding to a ∼25-30 μs delay. The mechanisms by which the air-born signal is collected and delivered to the cochlea are not thoroughly understood, and the source of the delay is controversial. We investigated these issues by observing ossicular motion along a single line of sight, roughly parallel to the EC and perpendicular to the stapes footplate. Measurements were made at the umbo, the long process of the manubrium, across the malleus-incus joint, at the long process of the incus, and the stapes head. While the overall delay between EC pressure and stapes velocity was fairly constant with frequency, subcomponents of the delay were frequency dependent. Up to ∼17 kHz, most of the overall delay was between the EC and umbo with a much smaller contribution along the ossicles, whereas in the range from ∼17 to 30 kHz, more of the overall delay was along the ossicles.

A fatty acid desaturase modulates the activation of defense signaling pathways in plants

Salicylic acid (SA) plays an important role in activating various plant defense responses, including expression of the pathogenesis-related (PR) genes and systemic acquired resistance. A critical positive regulator of the SA signaling pathway in Arabidopsis is encoded by the NPR1 gene. However, there is growing evidence that NPR1-independent pathways can also activate PR expression and disease resistance. To elucidate the components associated with NPR1-independent defense signaling, we isolated a suppressor of the npr1-5 allele, designated ssi2. The recessive ssi2 mutation confers constitutive PR gene expression, spontaneous lesion formation, and enhanced resistance to Peronospora parasitica. In contrast, a subset of defense responses regulated by the jasmonic acid (JA) signaling pathway, including expression of the defensin gene PDF1.2 and resistance to Botrytis cinerea, is impaired in ssi2 plants. With the use of a map-based approach, the SSI2 gene was cloned and shown to encode a stearoyl-ACP desaturase (S-ACP DES). S-ACP DES is an archetypical member of a family of soluble fatty acid (FA) desaturases; these enzymes play an important role in regulating the overall level of desaturated FAs in the cell. The activity of mutant S-ACP DES enzyme was reduced 10-fold, resulting in elevation of the 18:0 FA content in ssi2 plants. Because reduced S-ACP DES activity leads to the induction of certain defense responses and the inhibition of others, we propose that a FA-derived signal modulates crosstalk between different defense signaling pathways.

Environmentally sensitive, SA-dependent defense responses in the cpr22 mutant of Arabidopsis

To investigate the signaling pathways through which defense responses are activated following pathogen infection, we have isolated and characterized the cpr22 mutant. This plant carries a semidominant, conditional lethal mutation that confers constitutive expression of the pathogenesis-related (PR) genes PR-1, PR-2, PR-5 and the defensin gene PDF1.2. cpr22 plants also display spontaneous lesion formation, elevated levels of salicylic acid (SA) and heightened resistance to Peronospora parasitica Emco5. The cpr22 locus was mapped to chromosome 2, approximately 2 cM telomeric to the AthB102 marker. By analyzing the progeny of crosses between cpr22 plants and either NahG transgenic plants or npr1 mutants, all of the cpr22-associated phenotypes except PDF1.2 expression were found to be SA dependent. However, the SA signal transducer NPR1 was required only for constitutive PR-1 expression. A cross between cpr22 and ndr1-1 mutants revealed that enhanced resistance to P. parasitica is mediated by an NDR1-dependent pathway, while the other cpr22-induced defenses are not. Crosses between either coi1-1 or etr1-1 mutants further demonstrated that constitutive PDF1.2 expression is mediated by a JA- and ethylene-dependent pathway. Based on these results, the cpr22 mutation appears to induce its associated phenotypes by activating NPR1-dependent and NPR1-independent branches of the SA pathway, as well as an ethylene/JA signaling pathway. Interestingly, the SA-dependent phenotypes, but not the SA-independent phenotypes, are suppressed when cpr22 mutants are grown under high humidity.

A recessive mutation in the Arabidopsis SSI2 gene confers SA- and NPR1-independent expression of PR genes and resistance against bacterial and oomycete pathogens

The Arabidopsis thaliana NPR1 gene is required for salicylic acid (SA)-induced expression of pathogenesis-related (PR) genes and systemic acquired resistance. However, loss-of-function mutations in NPR1 do not confer complete loss of PR gene expression or disease resistance. Thus these responses also can be activated via an NPR1-independent pathway that currently remain to be elucidated. The ssi2-1 mutant, identified in a genetic screen for suppressors of npr1-5, affects signaling through the NPR1-independent defense pathway(s). In comparison with the wild-type (SSI2 NPR1) plants and the npr1-5 mutant (SSI2 npr1-5), the ssi2-1 npr1-5 double mutant and the ssi2-1 NPR1 single mutant constitutively express PR genes [PR-1, BGL2 (PR-2) and PR-5]; accumulate elevated levels of SA; spontaneously develop lesions; and possess enhanced resistance to a virulent strain of Peronospora parasitica. The ssi2-1 mutation also confers enhanced resistance to Pseudomonas syringae pv. tomato (Pst); however, this is accomplished primarily via an NPR1-dependent pathway. Analysis of ssi2-1 NPR1 nahG and ssi2-1 npr1-5 nahG plants revealed that elevated SA levels were not essential for the ssi2-1-conferred phenotypes. However, expression of the nahG transgene did reduce the intensity of some ssi2-1-conferred phenotypes, including PR-1 expression, and disease resistance. Based on these results, SSI2 or an SSI2-generated signal appears to modulate signaling of an SA-dependent, NPR1-independent defense pathway, or an SA- and NPR1-independent defense pathway.

Nitric oxide and salicylic acid signaling in plant defense

Salicylic acid (SA) plays a critical signaling role in the activation of plant defense responses after pathogen attack. We have identified several potential components of the SA signaling pathway, including (i) the H(2)O(2)-scavenging enzymes catalase and ascorbate peroxidase, (ii) a high affinity SA-binding protein (SABP2), (iii) a SA-inducible protein kinase (SIPK), (iv) NPR1, an ankyrin repeat-containing protein that exhibits limited homology to IkappaBalpha and is required for SA signaling, and (v) members of the TGA/OBF family of bZIP transcription factors. These bZIP factors physically interact with NPR1 and bind the SA-responsive element in promoters of several defense genes, such as the pathogenesis-related 1 gene (PR-1). Recent studies have demonstrated that nitric oxide (NO) is another signal that activates defense responses after pathogen attack. NO has been shown to play a critical role in the activation of innate immune and inflammatory responses in animals. Increases in NO synthase (NOS)-like activity occurred in resistant but not susceptible tobacco after infection with tobacco mosaic virus. Here we demonstrate that this increase in activity participates in PR-1 gene induction. Two signaling molecules, cGMP and cyclic ADP ribose (cADPR), which function downstream of NO in animals, also appear to mediate plant defense gene activation (e.g., PR-1). Additionally, NO may activate PR-1 expression via an NO-dependent, cADPR-independent pathway. Several targets of NO in animals, including guanylate cyclase, aconitase, and mitogen-activated protein kinases (e.g., SIPK), are also modulated by NO in plants. Thus, at least portions of NO signaling pathways appear to be shared between plants and animals.

Resistance to turnip crinkle virus in Arabidopsis is regulated by two host genes and is salicylic acid dependent but NPR1, ethylene, and jasmonate independent

Inoculation of turnip crinkle virus (TCV) on the resistant Arabidopsis ecotype Dijon (Di-17) results in the development of a hypersensitive response (HR) on the inoculated leaves. To assess the role of the recently cloned HRT gene in conferring resistance, we monitored both HR and resistance (lack of viral spread to systemic tissues) in the progeny of a cross between resistant Di-17 and susceptible Columbia plants. As expected, HR development segregated as a dominant trait that corresponded with the presence of HRT. However, all of the F(1) plants and three-fourths of HR(+) F(2) plants were susceptible to the virus. These results suggest the presence of a second gene, termed RRT, that regulates resistance to TCV. The allele present in Di-17 appears to be recessive to the allele or alleles present in TCV-susceptible ecotypes. We also demonstrate that HR formation and TCV resistance are dependent on salicylic acid but not on ethylene or jasmonic acid. Furthermore, these phenomena are unaffected by mutations in NPR1. Thus, TCV resistance requires a yet undefined salicylic acid-dependent, NPR1-independent signaling pathway.

Members of the Arabidopsis HRT/RPP8 family of resistance genes confer resistance to both viral and oomycete pathogens

Turnip crinkle virus (TCV) inoculation onto TCV-resistant Arabidopsis leads to a hypersensitive response (HR) controlled by the dominant gene HRT. HRT is a member of the class of resistance (R) genes that contain a leucine zipper, a nucleotide binding site, and leucine-rich repeats. The chromosomal position of HRT and its homology to resistance gene RPP8 and two RPP8 homologs indicate that unequal crossing over and gene conversion may have contributed to HRT evolution. RPP8 confers resistance to an oomycete pathogen, Peronospora parasitica. Despite very strong similarities within the HRT/RPP8 family, HRT and RPP8 are specific for the respective pathogens they detect. Hence, the HRT/RPP8 family provides molecular evidence that sequence changes between closely related members of multigene families can generate novel specificities for radically different pathogens. Transgenic plants expressing HRT developed an HR but generally remained susceptible to TCV because of a second gene, RRT, that regulates resistance to TCV. However, several transgenic plants that overexpressed HRT produced micro-HRs or no HR when inoculated with TCV and were resistant to infection. Expression of the TCV coat protein gene in seedlings containing HRT resulted in massive necrosis and death, indicating that the avirulence factor detected by the HRT-encoded protein is the TCV coat protein.

The Arabidopsis ssi1 mutation restores pathogenesis-related gene expression in npr1 plants and renders defensin gene expression salicylic acid dependent

The Arabidopsis NPR1 gene was previously shown to be required for the salicylic acid (SA)- and benzothiadiazole (BTH)-induced expression of pathogenesis-related (PR) genes and systemic acquired resistance. The dominant ssi1 (for suppressor of SA insensitivity) mutation characterized in this study defines a new component of the SA signal transduction pathway that bypasses the requirement of NPR1 for expression of the PR genes and disease resistance. The ssi1 mutation caused PR (PR-1, BGL2 [PR-2], and PR-5) genes to be constitutively expressed and restored resistance to an avirulent strain of Pseudomonas syringae pv tomato in npr1-5 (previously called sai1) mutant plants. In addition, ssi1 plants were small, spontaneously developed hypersensitive response-like lesions, accumulated elevated levels of SA, and constitutively expressed the antimicrobial defensin gene PDF1.2. The phenotypes of the ssi1 mutant are SA dependent. When SA accumulation was prevented in ssi1 npr1-5 plants by expressing the SA-degrading salicylate hydroxylase (nahG) gene, all of the phenotypes associated with the ssi1 mutation were suppressed. However, lesion formation and expression of the PR genes were restored in these plants by the application of BTH. Interestingly, expression of PDF1.2, which previously has been shown to be SA independent but jasmonic acid and ethylene dependent, was also suppressed in ssi1 npr1-5 plants by the nahG gene. Furthermore, exogenous application of BTH restored PDF1.2 expression in these plants. Our results suggest that SSI1 may function as a switch modulating cross-talk between the SA- and jasmonic acid/ethylene-mediated defense signal transduction pathways.

Production and secretion of biologically active human epidermal growth factor in Yarrowia lipolytica

The gene encoding human epidermal growth factor (hEGF) was expressed as a fusion protein with the leader peptide and pro I region of alkaline extracellular protease in the yeast Yarrowia lipolytica. hEGF was purified from culture supernatant by reverse-phase chromatography and analysed by Western-blot hybridisations. The biologically active hEGF in the purified sample was assayed using the radioreceptor assay and estimated to be 100 microg/l. However, the level of expression was found to be substantially low compared to the levels of homologous protein, alkaline extracellular protease (AEP), possibly due to degradation by secreted acid protease(s). A novel and sensitive bioassay was developed to determine the biological activity of hEGF produced at low levels and is based on the effect produced by hEGF in the regenerating tails of the wall lizard. Intramuscular injections of culture supernatant from the recombinant yeast and the standard hEGF led to a drastic reduction in tail regeneration confirming the biological activity of the recombinant hEGF.

Organisation and molecular analysis of repeated DNA sequences in the rice blast fungus Magnaporthe grisea

The distribution of a previously described repeated DNA sequence present as a 1.3-kb PstI fragment in the genome of the rice blast fungus Magnaporthe grisea was analysed by carrying out DNA fingerprint analysis of 36 isolates including rice, non-rice and laboratory strains. The analysis of various higher-molecular-weight PstI fragments with homology to the 1.3-kb repeat revealed that these may arise predominantly from transposon insertions or point mutations. Analysis of a 5.1-kb derivative revealed both a point mutation at a PstI site and an insertion of a putative transposable element which caused an increase in molecular weight from 1.3 to 5.1 kb. Another repeat element of 1.4 kb was identified and found to exist in association with the 1.3-kb repeat. Both 1.3- and 1.4-kb elements were found to be parts of MGR583 (Hamer et al. 1989), a LINE-like element. These elements were present in a high copy number in all the rice and a majority of non-rice pathogens indicating that MGR583 is not a host-specific sequence as reported earlier. Our results suggest that repeated DNA elements in M. grisea have amplified independently of one another and further indicate that different isolates of M. grisea may have evolved from several distinct lines of origin.

Analysis of host-induced response in the rice blast fungus Magnaporthe grisea using two-dimensional polyacrylamide gel electrophoresis

Two-dimensional (2-D) polyacrylamide gel electrophoresis of proteins was used to study the response of the rice blast fungus to extracts prepared from resistant and susceptible rice cultivars. A protein of molecular mass 31 kDa was induced by a susceptible host extract, while the fungus exposed to extract from the resistant cultivar and the untreated samples did not show the presence of this protein. Levels of this 31 kDa protein increased 30-fold, 72 h after treatment with plant extracts, with the concomitant appearance of at least sixteen other novel proteins. Fungus treated with extracts of resistant host or the untreated samples did not show any of these proteins while the proteins specific to different growth stages appeared as expected. Analysis of the extracellular samples showed induction of a 17 kDa protein after 72 h in the culture treated with susceptible host extract. Since the resistant host extract does not cause induction of any protein it is likely that the proteins induced in response to the susceptible host are expressed during the disease process and/or its establishment. Our study demonstrates usefulness of 2-D analysis in understanding host-pathogen interactions.

Mg-SINE: a short interspersed nuclear element from the rice blast fungus, Magnaporthe grisea

A short interspersed nuclear element, Mg-SINE, was isolated and characterized from the genome of the rice blast fungus, Magnaporthe grisea. Mg-SINE was isolated as an insertion element within Pot2, an inverted-repeat transposon from M. grisea and shows typical features of a mammalian SINE. Mg-SINE is present as a 0.47-kb interspersed sequence at approximately 100 copies per haploid genome in both rice and non-rice isolates of M. grisea, indicating a common evolutionary origin. Secondary structure analysis of Mg-SINE revealed a tRNA-related region at the 5' end which folds into a cloverleaf structure. Genomic fusions resulting in chimeric Mg-SINEs (Ch-SINEs) composed of a sequence homologous to Mg-SINE at the 3' end and an unrelated sequence at its 5' end were also isolated, indicating that this and other DNA rearrangements mediated by these elements may have a major effect on the genomic architecture of this fungus.

Pot2, an inverted repeat transposon from the rice blast fungus Magnaporthe grisea

We report the cloning and characterisation of Pot2, a putative transposable element from Magnaporthe grisea. The element is 1857 bp in size, has 43-bp perfect terminal inverted repeats (TIRs) and 16-bp direct repeats within the TIRs. A large open reading frame, potentially coding for a transposase-like protein, was identified. This putative protein coding region showed extensive identity to that of Fot1, a transposable element from another phytopathogenic fungus, Fusarium oxysporum. Pot2, like the transposable elements Tc1 and Mariner of Caenorhabditis elegans and Drosophila, respectively, duplicates the dinucleotide TA at the target insertion site. Sequence analysis of DNA flanking 12 Pot2 elements revealed similarity to the consensus insertion sequence of Tc1. Pot2 is present at a copy number of approximately 100 per haploid genome and represents one of the major repetitive DNAs shared by both rice and non-rice pathogens of M. grisea.