Background Immunocompetent animal models are required to study tumor-host interactions, immunotherapy, and immunotherapeutic combinations, however the currently available immunocompetent lung cancer models have substantial limitations. While orthotopic models potentially help fill this gap, the utility of these models has been limited by the very small number of murine lung cancer cell lines capable of forming orthotopic tumors in immunocompetent C57BL/6 hosts. Methods Primary lung tumors with specific genetic alterations were created in C57BL/6 background mice. These tumors were then passaged through other animals to increase tumorigenicity and select for the ability to grow in a non-self animal. Once tumors demonstrated growth in a non-self host, cell lines were established. Successful cell lines were evaluated for the ability to produce orthotopic lung tumors in immunocompetent hosts. Results We produced six murine lung cancer lines capable of orthotopic lung tumor formation in immunocompetent C57BL/6 animals. These lines demonstrate the expected genetic alterations based on their primary tumor genetics. Conclusions These novel cell lines will be useful for evaluating tumor-host interactions, the impact of specific oncogenic alterations on the tumor microenvironment, and immunotherapeutic approaches. This method of generating murine lines capable of orthotopic growth can likely be applied to other tumors and will broaden the applicability of pre-clinical testing of immunotherapeutic treatment regimens.

tumors collected within 48 hours after death. Rapidly collected advanced or drug resistant tumors allows for the study of molecular basis of lung cancer. The purpose of this study was to report logistics, ethical implications, and results of a pilot RTD program at Moffitt Cancer Center (MCC). Physicians discussed RTD with advanced lung cancer patients. Consented patients' health was monitored and staff notified when patients entered hospice. Shortly after death the body was transported and retrievals were conducted by a medical examiner within 24-48 hours of death. Samples were frozen or preserved in formalin and stored by MCC Tissue Core. Results: Twenty patients consented to participate in RTD between 2015 and 2016. Seven patients died and their tissues collected including primary, metastatic and normal tissue, and blood samples. Logistical challenges included: high costs and variability per case depending on county of death and final arrangements; availability of autopsy facility, and hospice communication. Weekend deaths were challenging due to limited staff resources. Histology evaluation of metastatic samples demonstrated minimal postmortem damage, confirming RTD provides high quality tissue. Conclusions: There are logistical challenges in developing a RTD program, but with communication and coordination, this program can succeed. Collection of tissue through RTD is attainable and beneficial for cancer research.

Adenoviral vectors expressing Cre recombinase are commonly used to initiate tumor formation in murine lung cancer models. While these vectors are designed to target genetic recombination to lung epithelial cells, adenoviruses can infect additional cell types that potentially influence tumor development. Our goal was to explore the consequences of adenoviral-mediated alveolar macrophage (AM) transduction in a Kras-initiated lung tumor model. As expected, treatment of animals harboring the KrasLSL-G12D allele and an inducible green fluorescence protein (GFP) tracking allele with an adenoviral vector expressing Cre recombinase under the control of the cytomegalovirus (CMV) promoter (Ad5-CMV-Cre), caused GFP-positive lung adenocarcinomas. Surprisingly, however, up to 70% of the total GFP+ cells were AM, and GFP+ AM could be detected 6 months after tumor initiation, and transduced AM demonstrated Kras activation and increased proliferation. In contrast, recombination was not detected in other immune cell populations and AM recombination could be eliminated by tumor initiation with an adenovirus expressing Cre recombinase under the control of the surfactant protein C (SPC) promoter. In addition, AM isolated from KrasLSL-G12D animals and transduced by Ad5-CMV-Cre ex vivo displayed prolonged survival in vitro and increased the growth of murine lung adenocarcinoma CMT/167 cells when co-injected in an orthotopic flank model. Given the importance of the immune system in tumor development and progression, inadvertent AM transduction by Ad5-CMV-Cre merits careful consideration during lung cancer model selection particularly if studies evaluating the tumor-immune interactions are planned.