Faculty Bibliography

In the present work we show that multiple lung cancer cell lines contain cisplatin resistant cell subpopulations expressing the Colony-Stimulating-Factor-Receptor-1 (CSF-1R) and surviving chemotherapy-induced stress. By exploiting siRNA-mediated knock down in vitro and the use of an investigational CSF-1R TKI (JNJ-40346527) in vitro and in vivo, we show that expression and function of the receptor are required for the clonogenicity and chemoresistance of the cell lines. Thus, inhibition of the kinase activity of the receptor reduced the levels of EMT-associated genes, stem cell markers and chemoresistance genes. Additionally, the number of high aldehyde dehydrogenase (ALDH) expressing cells was reduced, consequent to the lack of cisplatin-induced increase of ALDH isoforms. This affected the collective chemoresistance of the treated cultures. Treatment of tumor bearing mice with JNJ-40346527, at pharmacologically relevant doses, produced strong chemo-sensitizing effects in vivo. These anticancer effects correlated with a reduced number of CSF-1Rpos cells, in tumors excised from the treated mice. Depletion of the CD45pos cells within the treated tumors did not, apparently, play a major role in mediating the therapeutic response to the TKI. Thus, lung cancer cells express a functional CSF-1 and CSF-1R duo which mediates pro-tumorigenic effects in vivo and in vitro and can be targeted in a therapeutically relevant way. These observations complement the already known role for the CSF-1R at mediating the pro-tumorigenic properties of tumor-infiltrating immune components.

On November 9 and 10, 2015, the International Conference on Mesothelioma in Populations Exposed to Naturally Occurring Asbestiform Fibers was held at the University of Hawaii Cancer Center in Honolulu, Hawaii. The meeting was cosponsored by the International Association for the Study of Lung Cancer, and the agenda was designed with significant input from staff at the U.S. National Cancer Institute and National Institute of Environmental Health Sciences. A multidisciplinary group of participants presented updates reflecting a range of disciplinary perspectives, including mineralogy, geology, epidemiology, toxicology, biochemistry, molecular biology, genetics, public health, and clinical oncology. The group identified knowledge gaps that are barriers to preventing and treating malignant mesothelioma (MM) and the required next steps to address barriers. This manuscript reports the group's efforts and focus on strategies to limit risk to the population and reduce the incidence of MM. Four main topics were explored: genetic risk, environmental exposure, biomarkers, and clinical interventions. Genetics plays a critical role in MM when the disease occurs in carriers of germline BRCA1 associated protein 1 mutations. Moreover, it appears likely that, in addition to BRCA1 associated protein 1, other yet unknown genetic variants may also influence the individual risk for development of MM, especially after exposure to asbestos and related mineral fibers. MM is an almost entirely preventable malignancy as it is most often caused by exposure to commercial asbestos or mineral fibers with asbestos-like health effects, such as erionite. In the past in North America and in Europe, the most prominent source of exposure was related to occupation. Present regulations have reduced occupational exposure in these countries; however, some people continue to be exposed to previously installed asbestos in older construction and other settings. Moreover, an increasing number of people are being exposed in rural areas that contain noncommercial asbestos, erionite, and other mineral fibers in soil or rock (termed naturally occurring asbestos [NOA]) and are being developed. Public health authorities, scientists, residents, and other affected groups must work together in the areas where exposure to asbestos, including NOA, has been documented in the environment to mitigate or reduce this exposure. Although a blood biomarker validated to be effective for use in screening and identifying MM at an early stage in asbestos/NOA-exposed populations is not currently available, novel biomarkers presented at the meeting, such as high mobility group box 1 and fibulin-3, are promising. There was general agreement that current treatment for MM, which is based on surgery and standard chemotherapy, has a modest effect on the overall survival (OS), which remains dismal. Additionally, although much needed novel therapeutic approaches for MM are being developed and explored in clinical trials, there is a critical need to invest in prevention research, in which there is a great opportunity to reduce the incidence and mortality from MM.

Mutations in the epidermal growth factor receptor (EGFR) represent one of the most common "actionable" alterations in non-small cell lung cancer (NSCLC). Typified by high response rates to targeted therapies, EGFR tyrosine kinase inhibitors (TKI) are now established first-line treatment options and have transformed the treatment paradigm for NSCLC. With the recent breakthrough designation and approval of osimertinib, a 3rd generation EGFR TKI, available systemic and local treatment options have expanded, requiring new clinical algorithms that take into account individual patient molecular and clinical profiles. In this International Association for the Study of Lung Cancer (IASLC) commissioned consensus statement, key pathologic, diagnostic and therapeutic considerations, such as optimal choice of EGFR TKI and management of brain metastasis, are discussed. In addition, recommendations are made for clinical guidelines and research priorities, such as the role of re-biopsies and use of circulating free DNA (cfDNA) for molecular studies. With the rapid pace of progress in treating EGFR mutant NSCLC, this statement provides a state-of-the-art review of the contemporary issues in managing this unique subgroup of patients.

PURPOSE: To determine whether serum levels of High Mobility Group Box Protein-1 (HMGB1) could differentiate malignant mesothelioma (MM) patients, asbestos-exposed individuals, and unexposed controls. EXPERIMENTAL DESIGN: Hyper-acetylated and non-acetylated HMGB1 (together referred to as total HMGB1) were blindly measured in blood collected from MM patients (n=22), individuals with verified chronic asbestos exposure (n=20), patients with benign pleural effusions (n=13) or malignant pleural effusions not due to MM (n=25), and healthy controls (n=20). Blood levels of previously proposed MM biomarkers fibulin-3, mesothelin, and osteopontin were also measured in non-healthy individuals. RESULTS: HMGB1 serum levels reliably distinguished MM patients, asbestos-exposed individuals, and unexposed controls. Total HMGB1 was significantly higher in MM patients and asbestos-exposed individuals compared to healthy controls. Hyper-acetylated HMGB1 was significantly higher in MM patients compared to asbestos-exposed individuals and healthy controls, and did not vary with tumor stage. At the cut-off value of 2.00 ng/ml, the sensitivity and specificity of serum hyper-acetylated HMGB1 in differentiating MM patients from asbestos-exposed individuals and healthy controls was 100%, outperforming other previously proposed biomarkers. Combining HMGB1 and fibulin-3 provided increased sensitivity and specificity in differentiating MM patients from patients with cytologically benign or malignant non-MM pleural effusion. CONCLUSIONS: Our results are significant and clinically relevant as they provide the first biomarker of asbestos exposure and indicate that hyper-acetylated HMGB1 is an accurate biomarker to differentiate MM patients from individuals occupationally exposed to asbestos and unexposed controls. A trial to independently validate these findings will start soon.

PURPOSE: Prognostic models for pleural mesothelioma (MPM) are needed to prevent potentially futile outcomes. We combined MPM plasma biomarkers with validated clinical prognostic indices to determine whether stratification of risk for death in 194 MPM patients improved. PATIENTS AND METHODS: Individuals were recruited from three different centers: a discovery cohort (83 MPM) created by combining patients from two US centers and a separate, independent cohort from Canada (111 MPM). Univariable/multivariable analyses were performed on the initial discovery and independent cohorts separately. In multivariable analyses, prognostic factors were adjusted for the Mesothelioma EORTC Prognostic Index (PI). The prognostic significance of adding plasma biomarker data to the PI was determined using the likelihood ratio test, comparing models with and without the addition of biomarker to the clinical PI. The predictive ability of the biomarker was then assessed formally using Harrell's c-index by applying the fitted model variables of the discovery cohort to the second, independent cohort, including and not including the biomarker with the PI. RESULTS: Higher levels of osteopontin and mesothelin were individually associated with worse prognosis after adjusting for the PI. In the independent cohort, incorporating either plasma osteopontin or mesothelin into the baseline predictive PI model substantively and statistically significantly improved Harrell's c-statistic. In the final prognostic model, log-osteopontin, EORTC CPI, and hemoglobin remained as independently significant predictors, and the entire prognostic model improved the optimism-corrected Harrell's c-index significantly from 0.718 (0.67-0.77) to 0.801 (0.77-0.84). CONCLUSION: These data suggest a possible role for preoperative plasma biomarkers to improve prognostic capability of the MPM EORTC PI.

Chronic lymphocytic leukemia (CLL) is the most common human leukemia, and transgenic mouse studies indicate that activation of the T-cell leukemia/lymphoma 1 (TCL1) oncogene is a contributing event in the pathogenesis of the aggressive form of this disease. While studying the regulation ofTCL1expression, we identified the microRNA clustermiR-4521/3676and discovered that these two microRNAs are associated with tRNA sequences and that this region can produce two small RNAs, members of a recently identified class of small noncoding RNAs, tRNA-derived small RNAs (tsRNAs). We further proved thatmiR-3676andmiR-4521are tsRNAs using Northern blot analysis. We found that, likets-3676,ts-4521is down-regulated and mutated in CLL. Analysis of lung cancer samples revealed that bothts-3676andts-4521are down-regulated and mutated in patient tumor samples. Because tsRNAs are similar in nature to piRNAs [P-element-induced wimpy testis (Piwi)-interacting small RNAs], we investigated whetherts-3676andts-4521can interact with Piwi proteins and found these two tsRNAs in complexes containing Piwi-like protein 2 (PIWIL2). To determine whether other tsRNAs are involved in cancer, we generated a custom microarray chip containing 120 tsRNAs 16 bp or more in size. Microarray hybridization experiments revealed tsRNA signatures in CLL and lung cancer, indicating that, like microRNAs, tsRNAs may have an oncogenic and/or tumor-suppressor function in hematopoietic malignancies and solid tumors. Thus, our results show that tsRNAs are dysregulated in human cancer.

Lung cancer continues to be a major global health problem with more than 1.6 million new patients diagnosed each year with this disease. However, significant progress is underway in both the prevention and treatment of lung cancer. Lung cancer therapy has now emerged as a "role model" for precision cancer medicine with several important therapeutic breakthroughs occurring during 2015. These advances have occurred primarily in the immunotherapy field and in treatments directed against tumors harboring specific oncogenic drivers. Our knowledge about molecular mechanisms for oncogenic driven tumors and about resistance to targeted therapies has increased quickly over the last year. As a result, several regulatory approvals of new agents have occurred; which significantly improve survival and quality of life for lung cancer patients with advanced disease. The International Association for the Study of Lung Cancer has gathered experts in different areas of lung cancer research and management to summarize the most significant scientific advancements related to prevention and therapy of lung cancer during the last year.

Germline BAP1 mutations predispose to several cancers, in particular malignant mesothelioma. Mesothelioma is an aggressive malignancy generally associated with professional exposure to asbestos. However, to date, we found that none of the mesothelioma patients carrying germline BAP1 mutations were professionally exposed to asbestos. We hypothesized that germline BAP1 mutations might influence the asbestos-induced inflammatory response that is linked to asbestos carcinogenesis, thereby increasing the risk of developing mesothelioma after minimal exposure. Using a BAP1(+/-) mouse model, we found that, compared with their wild-type littermates, BAP1(+/-) mice exposed to low-dose asbestos fibers showed significant alterations of the peritoneal inflammatory response, including significantly higher levels of pro-tumorigenic alternatively polarized M2 macrophages, and lower levels of several chemokines and cytokines. Consistent with these data, BAP1(+/-) mice had a significantly higher incidence of mesothelioma after exposure to very low doses of asbestos, doses that rarely induced mesothelioma in wild-type mice. Our findings suggest that minimal exposure to carcinogenic fibers may significantly increase the risk of malignant mesothelioma in genetically predisposed individuals carrying germline BAP1 mutations, possibly via alterations of the inflammatory response.

BACKGROUND: Recent computed tomography (CT) screening trials showed that it is effective for early detection of lung cancer, but were plagued by high false positive rates. Additional blood biomarker tests designed to complement CT screening and reduce false positive rates are highly desirable. OBJECTIVE: Identify blood-based metabolite biomarkers for diagnosing lung cancer. MEHTODS: Serum samples from subjects participating in a CT screening trial were analyzed using untargeted GC-TOFMS and HILIC-qTOFMS-based metabolomics. Samples were acquired prior to diagnosis (pre-diagnostic, n= 17), at-diagnosis (n= 25) and post-diagnosis (n= 19) of lung cancer and from subjects with benign nodules (n= 29). RESULTS: Univariate analysis identified 40, 102 and 30 features which were significantly different between subjects with malignant (pre-, at- and post-diagnosis) solitary pulmonary nodules (SPNs) and benign SPNs, respectively. Ten metabolites were consistently different between subjects presenting malignant (pre- and at-diagnosis) or benign SPNs. Three of these 10 metabolites were phosphatidylethanolamines (PE) suggesting alterations in lipid metabolism. Accuracies of 77%, 83% and 78% in the pre-diagnosis group and 69%, 71% and 67% in the at-diagnosis group were determined for PE(34:2), PE(36:2) and PE(38:4), respectively. CONCLUSIONS: This study demonstrates evidence of early metabolic alterations that can possibly distinguish malignant from benign SPNs. Further studies in larger pools of samples are warranted.