Patrick J. Villeneuve

Incidence, severity and perioperative risk factors for atrial fibrillation following pulmonary resection

OBJECTIVES Postoperative atrial fibrillation (PAF) occurs commonly following pulmonary resection. Our aims were to quantify the incidence and severity of PAF using the Thoracic Morbidity & Mortality classification system, and identify risk factors for PAF. METHODS All consecutive patients undergoing pulmonary resection at a single centre (January 2008 - April 2010) were enrolled. PAF was defined as postoperative, electrocardiographically documented and requiring initiation of pharmacological therapy. Univariate and multivariate analyses of risk factors associated with the development of PAF were conducted. RESULTS The incidence of PAF was 11.8% (n = 43) of 363 pulmonary resections (open: n = 173; 47.7%; video-assisted: n = 177; 48.8%; converted: n = 13; 3.6%): sublobar (n = 93; 25.6%), lobectomy (n = 237; 65.3%), bilobectomy (n = 7; 1.9%) and pneumonectomy (n = 24; 6.6%). Twenty-eight cases (65.1%) were uncomplicated/transient, and 15 cases (34.9%) were complicated/persistent PAF, defined as lasting for >7 days (40.0%), requiring cardioversion (13.3%), vasopressors (33.3%), in-hospital use of anticoagulants (46.7%) and/or anticoagulants on discharge (26.7%). Patients with PAF had increased mean lengths of hospital stay (10.5 days vs 6.9 days; P = 0.04). Peak onset of PAF occurred 2.5 (standard deviation (SD) ± 1.3) days after pulmonary resection, lasting for 1.8 ± 2.8 (mean, ±SD) days. Multivariate analysis identified (relative risk; 95% confidence interval): age ≥70 years (2.3; 1.1-5.1), history of angioplasty/stents/angina (4.0; 1.4-11.3), thoracotomy (3.6; 1.4-9.3), conversion to open thoracotomy (16.5; 2.2-124.0) and extent of surgery/stage (7.1; 1.0-49.4) as predictors of PAF. CONCLUSIONS While the majority of PAF is uncomplicated and transient, one-third of cases lead to persistence or major intervention. Age, coronary artery disease and extent of surgery/stage increase the risk of PAF following pulmonary resection. Identifying patients with elevated risk may lead to targeted prophylaxis to reduce the incidence of PAF.

Customized Viral Immunotherapy for HPV-Associated Cancer

Oncolytic Maraba virus can selectively infect HPV+ human cancers as well as generate substantial antitumor immunity. This resulted in complete destruction of advanced HPV+ tumors in mice, providing a promising immunological approach to combat HPV-associated cancer. The viral-transforming proteins E6 and E7 make human papillomavirus–positive (HPV+) malignancies an attractive target for cancer immunotherapy. However, therapeutic vaccination exerts limited efficacy in the setting of advanced disease. We designed a strategy to induce substantial specific immune responses against multiple epitopes of E6 and E7 proteins based on an attenuated transgene from HPV serotypes 16 and 18 that is incorporated into MG1-Maraba virotherapy (MG1-E6E7). Mutations introduced to the transgene abrogate the ability of E6 and E7 to perturb p53 and retinoblastoma, respectively, while maintaining the ability to invoke tumor-specific, multifunctional CD8+ T-cell responses. Boosting with MG1-E6E7 significantly increased the magnitude of T-cell responses compared with mice treated with a priming vaccine alone (greater than 50 × 106 E7-specific CD8+ T cells per mouse was observed, representing a 39-fold mean increase in boosted animals). MG1-E6E7 vaccination in the HPV+ murine model TC1 clears large tumors in a CD8+-dependent manner and results in durable immunologic memory. MG1-Maraba can acutely alter the tumor microenvironment in vivo and exploit molecular hallmarks of HPV+ cancer, as demonstrated by marked infection of HPV+ patient tumor biopsies and is, therefore, ideally suited as an oncolytic treatment against clinical HPV+ cancer. This approach has the potential to be directly translatable to human clinical oncology to tackle a variety of HPV-associated neoplasms that cause significant morbidity and mortality globally. Cancer Immunol Res; 5(10); 847–59. ©2017 AACR.

Monensin Inhibits Epidermal Growth Factor Receptor Trafficking and Activation: Synergistic Cytotoxicity in Combination with EGFR Inhibitors

Targeting the EGFR, with inhibitors such as erlotinib, represents a promising therapeutic option in advanced head and neck squamous cell carcinomas (HNSCC). However, they lack significant efficacy as single agents. Recently, we identified the ability of statins to induce synergistic cytotoxicity in HNSCC cells through targeting the activation and trafficking of the EGFR. However, in a phase I trial of rosuvastatin and erlotinib, statin-induced muscle pathology limited the usefulness of this approach. To overcome these toxicity limitations, we sought to uncover other potential combinations using a 1,200 compound screen of FDA-approved drugs. We identified monensin, a coccidial antibiotic, as synergistically enhancing the cytotoxicity of erlotinib in two cell line models of HNSCC, SCC9 and SCC25. Monensin treatment mimicked the inhibitory effects of statins on EGFR activation and downstream signaling. RNA-seq analysis of monensin-treated SCC25 cells demonstrated a wide array of cholesterol and lipid synthesis genes upregulated by this treatment similar to statin treatment. However, this pattern was not recapitulated in SCC9 cells as monensin specifically induced the expression of activation of transcription factor (ATF) 3, a key regulator of statin-induced apoptosis. This differential response was also demonstrated in monensin-treated ex vivo surgical tissues in which HMG-CoA reductase expression and ATF3 were either not induced, induced singly, or both induced together in a cohort of 10 patient samples, including four HNSCC. These results suggest the potential clinical utility of combining monensin with erlotinib in patients with HNSCC. Mol Cancer Ther; 13(11); 2559–71. ©2014 AACR.

Induction of Activating Transcription Factor 3 Is Associated with Cisplatin Responsiveness in Non–Small Cell Lung Carcinoma Cells

Non–small cell lung carcinoma (NSCLC) is the most common cause of cancer deaths, with platin-based combination chemotherapy the most efficacious therapies. Gains in overall survival are modest, highlighting the need for novel therapeutic approaches including the development of next-generation platin combination regimens. The goal of this study was to identify novel regulators of platin-induced cytotoxicity as potential therapeutic targets to further enhance platin cytotoxicity. Employing RNA-seq transcriptome analysis comparing two parental NSCLC cell lines Calu6 and H23 to their cisplatin-resistant sublines, Calu6cisR1 and H23cisR1, activating transcription factor 3 (ATF3) was robustly induced in cisplatin-treated parental sensitive cell lines but not their resistant sublines, and in three of six tumors evaluated, but not in their corresponding normal adjacent lung tissue (0/6). Cisplatin-induced JNK activation was a key regulator of this ATF3 induction. Interestingly, in both resistant sublines, this JNK induction was abrogated, and the expression of an activated JNK construct in these cells enhanced both cisplatin-induced cytotoxicity and ATF3 induction. An FDA-approved drug compound screen was employed to identify enhancers of cisplatin cytotoxicity that were dependent on ATF3 gene expression. Vorinostat, a histone deacetylase inhibitor, was identified in this screen and demonstrated synergistic cytotoxicity with cisplatin in both the parental Calu6 and H23 cell lines and importantly in their resistant sublines as well that was dependent on ATF3 expression. Thus, we have identified ATF3 as an important regulator of cisplatin cytotoxicity and that ATF3 inducers in combination with platins are a potential novel therapeutic approach for NSCLC.

Activating Transcription Factor 3 as a Novel Regulator of Chemotherapy Response in Breast Cancer

Anthracyclines, such as doxorubicin, are used as first-line chemotherapeutics, usually in combination therapies, for the treatment of advanced breast cancer. While these drugs have been successful therapeutic options, their use is limited due to serious drug related toxicities and acquired tumor resistance. Uncovering the molecular mechanisms that mediate doxorubicins cytotoxic effect will lead to the identification of novel more efficacious combination therapies and allow for reduced doses of doxorubicin to be administered while maintaining efficacy. In our study, we demonstrate that activating transcription factor (ATF) 3 expression was upregulated by doxorubicin treatment in a representative panel of human breast cancer cell lines MCF7 and MDA-MB-231. We have also shown that doxorubicin treatment can induce ATF3 expression in ex vivo human breast and ovarian tumor samples. The upregulation of ATF3 in the cell lines was regulated by multiple cellular mechanisms including the activation of JNK and ATM signaling pathways. Importantly, loss of ATF3 expression resulted in reduced sensitivity to doxorubicin treatment in mouse embryonic fibroblasts. Through a 1200 FDA-approved compound library screen, we identified a number of agents whose cytotoxicity is dependent on ATF3 expression that also enhanced doxorubicin induced cytotoxicity. For example, the combination of the HDAC inhibitor vorinostat or the nucleoside analogue trifluridine could synergistically enhance doxorubicin cytotoxicity in the MCF7 cell line. Synergy in cell lines with the combination of ATF3 inducers and patients with elevated basal levels of ATF3 shows enhanced response to chemotherapy. Taken together, our results demonstrate a role for ATF3 in mediating doxorubicin cytotoxicity and provide rationale for the combination of ATF3-inducing agents with doxorubicin as a novel therapeutic approach.