Jung, M. Katherine

Abstract Pulmonary fibrosis is a significant complication in cancer patients treated with radiation or various chemotherapeutic agents. One such reagent, bleomycin, is used to treat a variety of cancers including, but not limited to, lymphoma, ovarian cancer, and melanoma. Its efficacy, however, is impacted by the incidence of significant pulmonary fibrosis, which often becomes dose limiting. In studies investigating the role(s) of metabolism in the profibrotic actions of transforming growth factor beta, we previously determined that increased fatty acid synthase (FASN) expression was observed in the fibrotic areas of lungs from idiopathic pulmonary fibrosis (IPF) patients compared to healthy controls. In that FASN levels are significantly increased in numerous human tumors including breast, prostate, colorectal, and ovarian, we wished to integrate these findings by examining whether inhibiting FASN activity could reduce pulmonary fibrosis. To that end, the cerulenin-derived FASN inhibitor C75 was tested in a murine treatment model of bleomycin-induced lung fibrosis. Following addition of C75, there was significant diminution in a number of profibrotic targets including collagen 1α1, fibronectin, connective tissue growth factor, and total lung collagen as assessed by hydroxyproline content. Not only was there a C75 dose-dependent decrease in the aforementioned targets, but lung function as assessed by peripheral blood oxygenation (on room air) was also stabilized/improved. Thus, FASN inhibition might reflect a possible target to maintain normal lung physiology in the context of cancer chemotherapy. This work was supported by Public Health Service grants GM-055816 and GM-054200 from the National Institutes of General Medical Sciences. Citation Format: Mi-Yeon Jung. Fatty acid synthase is a risk factor for bleomycin-induced lung fibrosis in mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 346. doi:10.1158/1538-7445.AM2017-346

Abstract Oncolytic replication competent viruses are increasingly being tested in clinical trials. Their optimal use would be greatly facilitated by technologies that enable repeated and quantitative estimation of the location and population size of the virus as it propagates within the tumor. To address this, we have generated two replication competent measles viruses (MV) that express the thyroidal sodium iodide symporter (NIS) in injected cells. One virus, MV-NIS is in Phase 1 clinical trials and kills cells by formation of syncytia. The second virus, MV-I98A-NIS has a mutation in the MV hemagglutinin protein that prevents syncytium formation and kills cells by lysis. Cells infected with MV-I98A-NIS remain viable for longer compared to MV-NIS and are expected to express higher concentrations of NIS, facilitating in vivo imaging. BxPC-3 human pancreatic carcinoma cells were implanted in the flank of nude mice. Subsequently, the mice were injected with Opti-MEM (control), MV-NIS or MV-I98A-NIS (1x107 TCID50/ml) via the tail vein. On days 3, 5, 8, 10, 12, 15, 17 and 19 after virus injection, mice from the control, and virus injected groups were imaged with SPECT/CT (U-SPECT II) 1 hour after injection of 99mTc. Immediately afterwards, the mice were euthanized, the tumors excised, weighed and isotope activity measured. The tumors were divided into parts for histologic analysis and RNA extraction. NIS gene expression was determined by Q-RT-PCR and immunohistochemistry, while viral genome copy number was determined by Q-RT-PCR for the nucleoprotein (N). Image analysis using ROI was performed using AMIDE with background correction across all imaging planes. There was no correlation between tumor mass (volume) and isotope uptake (R2=0.0001 and 0.0051 for MV-NIS and MV-I98A-Nis respectively) suggesting that isotope uptake was strictly linked to virus infection. There was a strong, linear correlation between the levels of virus dependent NIS expression and isotope activity within the tumor (R2=0.79 and 0.93 for MV-NIS and MV-I98A-NIS respectively). Tumors infected with MV-I98A-NIS had a higher concentration of isotope compared with MV-NIS (p<0.004) and a higher correlation coefficient of NIS isotope uptake versus NIS expression (14.1 mCi/NIS copies/ng RNA versus 11.5, p=0.003), compatible with the observation that tumor cells infected with MV-I98A-NIS remain viable for longer compared to MV-NIS. Activity within tumors increased as a function of time, compatible with ongoing virus replication and spread within the tumors. Correlation of imaging studies with NIS expression and viral genome copy number is ongoing. Our preliminary studies suggest that in vivo imaging can be used to accurately determine the size of the oncolytic virus population within a tumor as a function of time. These observations will be used to understand the dynamics of virus spread within tumors and optimize therapy. Citation Format: Mi-Yeon Jung, Matthew K. Ennis, Chetan P. Offord, David Dingli. Quantitative in vivo imaging of oncolytic virus replication. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4947. doi:10.1158/1538-7445.AM2014-4947