Orthotopic Lung Cancer Model Research Articles

A Method for Orthotopic Transplantation of Lung Cancer in Mice.

Preclinical mouse models of lung cancer have been vital experimental tools to elucidate cancer biology and test novel therapeutic regimens. Two main models are most commonly used-genetically engineered mouse models and xenograft transplantation models. The most common xenograft model employs subcutaneous transplantation of tumor cells. However, the subcutaneous space is a foreign environment to lung cancer cells and does not appropriately model the tumor-stromal interactions of endogenous lung cancers. Here, we present an orthotopic mouse model of lung cancer that utilizes direct injection of cancer cells into the lung parenchyma that allows many potential studies including interactions of lung fibroblast Hedgehog pathway activity and tumor epithelia. The protocol describes this procedure and its potential applications for lung cancer research.

Deep Learning Based Automated Orthotopic Lung Tumor Segmentation in Whole-Body Mouse CT-Scans.

Simple SummaryThe development of more translatable orthotopic mouse models is essential in order to study lung cancer more realistically. However, a major challenge in these orthotopic mouse models is the monitoring of tumor take, tumor growth and the detection of therapeutic effects. Therefore, the aim of this study was to train and validate a deep learning algorithm for fully automatic lung tumor quantification in whole-body mouse µCBCT scans. This deep learning application enables highly accurate longitudinal evaluation of tumor volume changes in mice with minimal operator involvement in the data analysis. In addition to longitudinal quantification of tumor development, the algorithm can also be deployed to optimize the randomization and 3R animal welfare aspects of the experimental design in preclinical studies.Lung cancer is the leading cause of cancer related deaths worldwide. The development of orthotopic mouse models of lung cancer, which recapitulates the disease more realistically compared to the widely used subcutaneous tumor models, is expected to critically aid the development of novel therapies to battle lung cancer or related comorbidities such as cachexia. However, follow-up of tumor take, tumor growth and detection of therapeutic effects is difficult, time consuming and requires a vast number of animals in orthotopic models. Here, we describe a solution for the fully automatic segmentation and quantification of orthotopic lung tumor volume and mass in whole-body mouse computed tomography (CT) scans. The goal is to drastically enhance the efficiency of the research process by replacing time-consuming manual procedures with fast, automated ones. A deep learning algorithm was trained on 60 unique manually delineated lung tumors and evaluated by four-fold cross validation. Quantitative performance metrics demonstrated high accuracy and robustness of the deep learning algorithm for automated tumor volume analyses (mean dice similarity coefficient of 0.80), and superior processing time (69 times faster) compared to manual segmentation. Moreover, manual delineations of the tumor volume by three independent annotators was sensitive to bias in human interpretation while the algorithm was less vulnerable to bias. In addition, we showed that besides longitudinal quantification of tumor development, the deep learning algorithm can also be used in parallel with the previously published method for muscle mass quantification and to optimize the experimental design reducing the number of animals needed in preclinical studies. In conclusion, we implemented a method for fast and highly accurate tumor quantification with minimal operator involvement in data analysis. This deep learning algorithm provides a helpful tool for the noninvasive detection and analysis of tumor take, tumor growth and therapeutic effects in mouse orthotopic lung cancer models.

1661P Antitumor efficacy and immune profiling of the mouse ortholog of nemvaleukin alfa, a novel engineered IL-2 fusion protein, in an orthotopic mouse model of small cell lung cancer alone or in combination with standard chemotherapy

Small cell lung cancer (SCLC) is a deadly cancer with a 5-year survival of less than 7%. Immune checkpoint blockade was recently approved but survival benefits are limited. nemvaleukin alfa (‘nemvaleukin’; formerly ALKS 4230), a novel engineered IL-2 fusion protein currently under phase I/II study, is designed to selectively expand tumor-killing CD8+ and NK cells. Here, utilizing a novel SCLC murine model, we investigated the effects of RDB 1462, the murine ortholog of nemvaleukin, on tumor growth and immune cell profiles.

Targeted Oral Delivery of Paclitaxel Using Colostrum-Derived Exosomes.

Simple SummaryPaclitaxel (PAC) is a widely used antitumor agent in the treatment of various early-stage and advanced cancers, including lung cancer. While efficacious, solvent-based PAC generally is not well tolerated and is associated with severe side effects. To overcome such limitations, naturally occurring nanocarriers such as exosomes are attracting great interest. In this paper, we show that tumor-targeted oral formulation of PAC, using bovine colostrum-derived exosomes, not only enhance therapeutic efficacy against orthotopic lung cancer but also mitigate or eliminate systemic and immunotoxicity of the conventional i.v. dosing. These data will leverage the advantages of bovine colostrum exosomes to advance the exosome-mediated targeted oral delivery of PAC as a therapeutic alternative to current therapies.Lung cancer is the leading cause of cancer-related deaths worldwide. Non-small-cell lung cancer (NSCLC) is the most common type accounting for 84% of all lung cancers. Paclitaxel (PAC) is a widely used drug in the treatment of a broad spectrum of human cancers, including lung. While efficacious, PAC generally is not well tolerated and its limitations include low aqueous solubility, and significant toxicity. To overcome the dose-related toxicity of solvent-based PAC, we utilized bovine colostrum-derived exosomes as a delivery vehicle for PAC for the treatment of lung cancer. Colostrum provided higher yield of exosomes and could be loaded with higher amount of PAC compared to mature milk. Exosomal formulation of PAC (ExoPAC) showed higher antiproliferative activity and inhibition of colony formation against A549 cells compared with PAC alone, and also showed antiproliferative activity against a drug-resistant variant of A549. To further enhance its efficacy, exosomes were attached with a tumor-targeting ligand, folic acid (FA). FA-ExoPAC given orally showed significant inhibition (>50%) of subcutaneous tumor xenograft while similar doses of PAC showed insignificant inhibition. In the orthotopic lung cancer model, oral dosing of FA-ExoPAC achieved greater efficacy (55% growth inhibition) than traditional i.v. PAC (24–32% growth inhibition) and similar efficacy as i.v. Abraxane (59% growth inhibition). The FA-ExoPAC given i.v. exceeded the therapeutic efficacy of Abraxane (76% growth inhibition). Finally, wild-type animals treated with p.o. ExoPAC did not show gross, systemic or immunotoxicity. Solvent-based PAC caused immunotoxicity which was either reduced or completely mitigated by its exosomal formulations. These studies show that a tumor-targeted oral formulation of PAC (FA-ExoPAC) significantly improved the overall efficacy and safety profile while providing a user-friendly, cost-effective alternative to bolus i.v. PAC and i.v. Abraxane.

Abstract 1899: Biochemical and functional characterization of mutant KRAS epitopes validates this oncoprotein for immunological targeting

Abstract Activating missense mutations within RAS oncogenes are among the most prevalent genomic alterations observed in human cancers and drive oncogenesis in the three most lethal tumor types. Emerging evidence suggests mutant KRAS (mKRAS) may be targeted immunologically, but mKRAS epitopes remain poorly defined. Here, we employ multi-omic approaches to characterize optimal HLA class I-restricted mKRAS epitopes. Using in silico epitope prediction, we identify candidate mKRAS G12 epitopes with high predicted binding affinity to prevalent HLA class I alleles. We utilize biochemical approaches to identify mKRAS epitopes with high measured binding affinity and stability to HLA-A*03:01, -A*11:01 and -B*07:02. Furthermore, we provide proteomic validation of epitope processing and presentation by these alleles. We report mKRAS G12V and G12R epitopes are immunogenic as evidenced by the isolation of mKRAS G12V- and G12R-specific TCRαβ from healthy donors. The transfer of mKRAS-TCRs to primary CD8+ T cells serves as sensitive probes to validate mKRAS epitope processing and presentation by tumor cells and confers cytotoxicity against mKRAS human tumor cell lines of various histologies. The kinetics of lytic activity correlate with measured TCR avidity and mKRAS/HLA class I complex abundance expressed on the tumor cell surface. Finally, the adoptive transfer of mKRAS-TCR engineered primary CD8+ T cells to NOD scid gamma mice leads to tumor eradication in an orthotopic mKRAS lung cancer model. This study validates mKRAS as a bona fide tumor neoantigen and supports strategies to identify recurrent driver alterations for immunological targeting. Based on this work, clinical studies targeting mKRAS in cancer patients using vaccines and adoptive T cell therapy are under active investigation. Citation Format: Adham S. Bear, Tatiana Blanchard, Mark H. O'Hara, John Scholler, Robert H. Vonderheide, Gerald P. Linette, Beatriz M. Carreno. Biochemical and functional characterization of mutant KRAS epitopes validates this oncoprotein for immunological targeting [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1899.

Abstract 2597: Non-clinical studies of systemic delivery of oncolytic virus arms with IL-12 and anti-PD-1 antibody

Abstract Background: Limited success has been reported with intravenous delivery of oncolytic viruses because of dilution of viruses in the blood volume, rapid clearance of viral particles and sequestration in non-target organs. We have reported construction of MVR-T3011, a recombinant oncolytic herpes virus embodies immunotherapeutic genes encoding IL-12 and anti-PD-1 antibody. Intratumoral Injection of MVR-T3011 has entered into clinical stage for the study of its safety and preliminary efficacy. Here we propose systemic delivery of MVR-T3011 by intravenous (IV) injection to treat tumor types that are not easily accessible by local injection. Methods: The pharmacological activity, safety and biodistribution of MVR-T3011 by intravenous injection have been studied in immune deficient and competent mouse model. Results: (i) In immune deficient mice, MVR-T3011 is enriched in tumor following tail vein injection. MVR-T3011 inhibits tumor growth of A549 xenograft. (ii) In immune competent mice, MVR-T1013L, the virus backbone carries a reporter gene encodes luciferase was enriched in upper abdomen and thorax 24hr following IV injection. (iii) IV administration of mouse surrogate oncolytic virus MVR-T3855 extended survival of mice in B16-F10 mouse melanoma lung metastasis model, LLC mouse orthotopic lung cancer model and H22 mouse orthotopic hepatocarcinoma model significantly. (iv) IV administration of MVR-T3855 delayed the onset of peritoneal effusion in H22 mouse hepatocarcinoma model significantly. (v) The biodistribution studies showed: following IV injection, tumor viral DNA reached peak level at 24hr, and dropped to baseline at 48hr; Subsequent injection showed similar patterns with lower peak levels. Consistent virus DNA level in the blood was detected without spike of viral DNA in other tissues probably due to non-complete virus genome circulating following virus clearance. Both IL-12 and anti-PD-1 antibody were detected in tissue and/or blood with low level 24hr following injection. Conclusions: MVR-T3011 is a suitable herpes oncolytic virus agent for intravenous injection through studies of pharmacological activity, safety and biodistribution. The significant finding reported in this article is clinical potential of herpes oncolytic virus for extensive metastatic tumors. Citation Format: Yanxin Zheng, Runbin Yan, Yuxin Tang, Borui Zhan, Yue Huang, Dongyao Ni, Xiaoqing Chen, Grace Zhou. Non-clinical studies of systemic delivery of oncolytic virus arms with IL-12 and anti-PD-1 antibody [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2597.

Therapeutic efficacy of cancer vaccine adjuvanted with nanoemulsion loaded with TLR7/8 agonist in lung cancer model

Although immune checkpoint inhibitors have significantly improved clinical outcomes in various malignant cancers, only a small proportion of patients reap benefits, likely due to the low number of T cells and high number of immunosuppressive cells in the tumor microenvironment (TME) of patients with advanced disease. We developed a cancer vaccine adjuvanted with nanoemulsion (NE) loaded with TLR7/8 agonist (R848) and analyzed its therapeutic effect alone or in combination with immune checkpoint inhibitors, on antitumor immune responses and the reprogramming of suppressive immune cells in the TME. NE (R848) demonstrated robust local and systemic antitumor immune responses in both subcutaneous and orthotopic mouse lung cancer models, inducing tumor-specific T cell activation and mitigating T cell exhaustion. Combination with anti-PD-1 antibodies showed synergistic effects with respect to therapeutic efficacy and survival rate. Thus, NE (R848)-based cancer vaccines could prevent tumor recurrence and prolong survival by activating antitumor immunity and reprogramming immunosuppression.

Orthotopic model of lung cancer: isolation of bone micro-metastases after tumor escape from Osimertinib treatment

BackgroundOsimertinib is a third generation tyrosine kinase inhibitor (TKI) that targets the epidermal growth factor receptor (EGFR) in lung cancer. However, although this molecule is not subject to some of the resistance mechanisms observed in response to first generation TKIs, ultimately, patients relapse because of unknown resistance mechanisms. New relevant non-small cell lung cancer (NSCLC) mice models are therefore required to allow the analysis of these resistance mechanisms and to evaluate the efficacy of new therapeutic strategies.MethodsBriefly, PC-9 cells, previously modified for luciferase expression, were injected into the tail vein of mice. Tumor implantation and longitudinal growth, almost exclusively localized in the lung, were evaluated by bioluminescence. Once established, the tumor was treated with osimertinib until tumor escape and development of bone metastases.ResultsMicro-metastases were detected by bioluminescence and collected for further analysis.ConclusionWe describe an orthotopic model of NSCLC protocol that led to lung primary tumor nesting and, after osimertinib treatment, by metastases dissemination, and that allow the isolation of these small osimertinib-resistant micro-metastases. This model provides new biological tools to study tumor progression from the establishment of a lung tumor to the generation of drug-resistant micro-metastases, mimicking the natural course of the disease in human NSCLC patients.

Long Noncoding RNA CTD-2245E15.3 Promotes Anabolic Enzymes ACC1 and PC to Support Non-Small Cell Lung Cancer Growth.

Long noncoding RNAs (lncRNA) have been shown to play critical regulatory roles in the onset and progression of human cancers. However, the functions of a large proportion of lncRNAs are still unexplored. Here we describe a novel lncRNA, CTD-2245E15.3, that promotes lung tumorigenesis by regulating the anabolic enzymes acetyl-CoA carboxylase 1 (ACC1, encoded by the ACACA gene) and pyruvate carboxylase (PC). Differentially expressed lncRNAs between non-small cell lung cancer (NSCLC) and paired adjacent nontumor tissues were identified by a microarray and validated using quantitative real-time polymerase chain reaction. CTD-2245E15.3 was significantly upregulated in NSCLC and was mainly located in the cytoplasm. Knockdown of CTD-2245E15.3 by specific antisense oligonucleotides suppressed cell growth in vitro and in vivo, largely due to cell-cycle arrest and induction of apoptosis. Overexpression of CTD-2245E15.3 in an orthotopic model of lung cancer led to a significant increase in total tumor burden. CTD-2245E15.3 exerted its oncogenic function by binding ACC1 and PC, which are key anabolic factors for biomolecule synthesis in rapidly proliferating tumor cells. Knockdown of CTD-2245E15.3 increased phosphorylation of ACC1 at an inhibitory site for enzymatic activity and promoted PC degradation via ubiquitination. Supplements of palmitate or oxaloacetate, products of ACC1 and PC, alleviated the suppression of cell growth caused by loss of CTD-2245E15.3. These findings reveal the important role of CTD-2245E15.3 as an oncogenic lncRNA in the anabolic process for tumor growth. SIGNIFICANCE: These findings demonstrate a novel lncRNA CTD-2245E15.3 that binds and positively regulates anabolic enzymes ACC1 and PC to promote tumor growth. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/13/3509/F1.large.jpg.

Fractionated Radiation Severely Reduces the Number of CD8+ T Cells and Mature Antigen Presenting Cells Within Lung Tumors.

The combination of standard-of-care radiation therapy (RT) with immunotherapy is moving to the mainstream of non-small cell lung cancer treatment. Multiple preclinical studies reported on the CD8+ T cell stimulating properties of RT, resulting in abscopal therapeutic effects. A literature search demonstrates that most preclinical lung cancer studies applied subcutaneous lung tumor models. Hence, in-depth immunologic evaluation of clinically relevant RT in orthotopic lung cancer models is lacking. We studied the therapeutic and immunologic effects of low-dose fractionated RT on lungs from C57BL/6 mice, challenged 2 weeks before with firefly luciferase expressing Lewis lung carcinoma cells via the tail vein. Low-dose fractionation was represented by 4 consecutive daily fractions of image guided RT at 3.2 Gy. We showed reduced lung tumor growth upon irradiation using in vivo bioluminescence imaging and immunohistochemistry. Moreover, significant immunologic RT-induced changes were observed in irradiated lungs and in the periphery (spleen and blood). First, a significant decrease in the number of CD8+ T cells and trends toward more CD4+ and regulatory T cells were seen after RT in all evaluated tissues. Notably, only in the periphery did the remaining CD8+ T cells show a more activated phenotype. In addition, a significant expansion of neutrophils and monocytes was observed upon RT locally and systemically. Locally, RT increased the influx of tumor-associated macrophages and conventional type 2 dendritic cells, whereas the alveolar macrophages and conventional type 1 DCs dramatically decreased. Functionally, these antigen-presenting cells severely reduced their CD86 expression, suggesting a reduced capacity to induce potent immunity. Our results imply that low-dose fractionated RT of tumor-bearing lung tissue shifts the immune cell balance toward an immature myeloid cell dominating profile. These data argue for myeloid cell repolarizing strategies to enhance the abscopal effects in patients with non-small cell lung cancer treated with fractionated RT.

Ze-Qi-Tang Formula Induces Granulocytic Myeloid-Derived Suppressor Cell Apoptosis via STAT3/S100A9/Bcl-2/Caspase-3 Signaling to Prolong the Survival of Mice with Orthotopic Lung Cancer.

Non-small-cell lung cancer (NSCLC) remains the most common malignancy with the highest morbidity and mortality worldwide. In our previous study, we found that a classic traditional Chinese medicine (TCM) formula Ze-Qi-Tang (ZQT), which has been used in the treatment of respiratory diseases for thousands of years, could directly inhibit the growth of human NSCLC cells via the p53 signaling pathway. In this study, we explored the immunomodulatory functions of ZQT. We found that ZQT significantly prolonged the survival of orthotopic lung cancer model mice by modulating the tumor microenvironment (TME). ZQT remarkably reduced the number of MDSCs (especially G-MDSCs) and inhibited their immunosuppressive activity by inducing apoptosis in these cells via the STAT3/S100A9/Bcl-2/caspase-3 signaling pathway. When G-MDSCs were depleted, the survival promotion effect of ZQT and its inhibitory effect on lung luminescence signal disappeared in tumor-bearing mice. This is the first study to illustrate the immunomodulatory effect of ZQT in NSCLC and the underlying molecular mechanism.

A novel oncotherapy strategy: Direct thrombin inhibitors suppress progression, dissemination and spontaneous metastasis in non-small cell lung cancer.

Cancer cachexia and cancer-associated thrombosis are potentially fatal outcomes of advanced cancer. Nevertheless, thrombin expression in non-small cell lung cancer (NSCLC) primary tumour tissues and the association between prognosis of NSCLC patients remain largely unknown. Clinical pathological analysis was performed to determine the relationship between thrombin and tumour progression. Effects of r-hirudin and direct thrombin inhibitor peptide (DTIP) on cancer progression were evaluated. Western blotting, immunohistochemistry, and immunofluorescence were used to explore the inhibition mechanism of r-hirudin and DTIP. The therapeutic effect of the combination of DTIP and chemotherapy was determined. Thrombin expression in NSCLC tissues was closely related to clinicopathological features and the prognosis of patients. Thrombin deficiency inhibited tumour progression. The novel thrombin inhibitors, r-hirudin and DTIP, inhibited cell invasion and metastasis in vitro. They inhibited tumour growth and metastasis in orthotopic lung cancer model, inhibited cell invasion, and prolonged survival after injection of tumour cells via the tail vein. They also inhibited angiogenesis and spontaneous metastases from subcutaneously inoculated tumours. The promotion by thrombin of invasion and metastasis was abolished in PAR-1-deficient NSCLC cells. r-hirudin and DTIP inhibited tumour progression through the thrombin-PAR-1-mediated RhoA and NF-κB signalling cascades via inhibiting MMP9 and IL6 expression. DTIP potentiated chemotherapy-induced growth and metastatic inhibition and inhibited chemotherapy-induced resistance in mice. Thrombin makes a substantial contribution, together with PAR-1, to NSCLC malignancy. The anti-coagulants, r-hirudin and DTIP, could be used in anti-tumour therapy and a combination of DTIP and chemotherapy might improve therapeutic effects.

Chronic intermittent hypoxia promoted lung cancer stem cell-like properties via enhancing Bach1 expression

BackgroundAn adverse role for obstructive sleep apnea (OSA) in cancer aggressiveness and mortality has recently emerged from clinical and animal studies, and the reasons have not been fully determined. Cancer stem cells (CSCs) are regarded as the main cause of carcinoma metastasis. So far, the relationship between OSA and lung CSCs has not been explored.MethodIn the present study, we established an orthotopic mouse model of primary lung cancer and utilized chronic intermittent hypoxia (CIH) exposure to mimic OSA status.ResultsWe observed that CIH endows lung cancer with greater metastatic potential, evidenced by increased tumor growth, tumor seeding, and upregulated CSC-related gene expression in the lungs. Notably, the transcription factor BTB and CNC homology 1 (Bach1), a key factor in responding to conditions of oxidative stress, is increased in lung cancer after CIH exposure in vitro and in vivo. Meanwhile, exposing lung cancer cells to CIH promoted cell proliferation, clonal diversity, induced stem-like cell marker expression, and gave rise to CSCs at a relatively higher frequency. Furthermore, the increase of mitochondrial ROS (mtROS) and CSC-marker expression induced by CIH exposure was abolished in Bach1 shRNA-treated lung cancer cells.ConclusionsOur results indicated that CIH promoted lung CSC-like properties by activating mtROS, which was partially mediated by Bach1.

Mesenchymal stromal cell delivery of oncolytic immunotherapy improves CAR-T cell antitumor activity

The immunosuppressive tumor microenvironment (TME) is a formidable barrier to the success of adoptive cell therapies for solid tumors. Oncolytic immunotherapy with engineered adenoviruses (OAd) may disrupt the TME by infecting tumor cells, as well as surrounding stroma, to improve the functionality of tumor-directed chimeric antigen receptor (CAR)-T cells, yet efficient delivery of OAds to solid tumors has been challenging. Here we describe how mesenchymal stromal cells (MSCs) can be used to systemically deliver a binary vector containing an OAd together with a helper-dependent Ad (HDAd; combinatorial Ad vector [CAd]) that expresses interleukin-12 (IL-12) and checkpoint PD-L1 (programmed death-ligand 1) blocker. CAd-infected MSCs deliver and produce functional virus to infect and lyse lung tumor cells while stimulating CAR-T cell anti-tumor activity by release of IL-12 and PD-L1 blocker. The combination of this approach with administration of HER.2-specific CAR-T cells eliminates 3D tumor spheroids invitro and suppresses tumor growth in two orthotopic lung cancer models invivo. Treatment with CAd MSCs increases the overall numbers of human Tcells invivo compared to CAR-T cell only treatment and enhances their polyfunctional cytokine secretion. These studies combine the predictable targeting of CAR-T cells with the advantages of cancer cell lysis and TME disruption by systemic MSC delivery of oncolytic virotherapy: incorporation of immunostimulation by cytokine and checkpoint inhibitor production through the HDAd further enhances anti-tumor activity.

Strategy to enhance dendritic cell-mediated DNA vaccination in the lung.

We here introduce a new paradigm to promote pulmonary DNA vaccination. Specifically, we demonstrate that nanoparticles designed to rapidly penetrate airway mucus (mucus-penetrating particle or MPP) enhance the delivery of inhaled model DNA vaccine (i.e. ovalbumin-expressing plasmids) to pulmonary dendritic cells (DC), leading to robust and durable local and trans-mucosal immunity. In contrast, mucus-impermeable particles were poorly taken up by pulmonary DC following inhalation, despite their superior ability to mediate DC uptake in vitro compared to MPP. In addition to the enhanced immunity achieved in mucosal surfaces, inhaled MPP unexpectedly provided significantly greater systemic immune responses compared to gold-standard approaches applied in the clinic for systemic vaccination, including intradermal injection and intramuscular electroporation. We also showed here that inhaled MPP significantly enhanced the survival of an orthotopic mouse model of aggressive lung cancer compared to the gold-standard approaches. Importantly, we discovered that MPP-mediated pulmonary DNA vaccination induced memory T-cell immunity, particularly the ready-to-act effector memory-biased phenotype, both locally and systemically. The findings here underscore the importance of breaching the airway mucus barrier to facilitate DNA vaccine uptake by pulmonary DC and thus to initiate full-blown immune responses.

In Vivo Imaging of Orthotopic Lung Cancer Models in Mice.

The success of anticancer interventions relies on their ability to ignite an anticancer immune response and to reinstate cancer immunosurveillance. Thus, high dose crizotinib can induce immunogenic cell death (ICD) in cancer cells. If combined with cisplatin, crizotinib sensitizes non-small cell lung cancers (NSCLC) to subsequent (but not simultaneous) immunotherapy with PD-1 immune checkpoint blockade, facilitating the cure of more than 90% of established orthotopic cancers in mice. Here, we detail protocols for the establishment and monitoring of transplantable orthotopic NSCLCs in syngeneic immunocompetent animals. Indeed, TC1 cells establish lung cancer upon their intravenous injection into the tail vein, while Lewis lung carcinoma (LLC) cells can be implanted intrathoracically to generate lung cancers. If transduced with luciferase, both TC1 and LLC cells form tumors that can be conveniently monitored by chemiluminescence. This type of NSCLC model is highly useful for the development of novel curative anticancer therapies.

Functional screening identifies aryl hydrocarbon receptor as suppressor of lung cancer metastasis

Lung cancer mortality largely results from metastasis. Despite curative surgery many patients with early-stage non-small cell lung cancer ultimately succumb to metastatic relapse. Current risk reduction strategies based on cytotoxic chemotherapy and radiation have only modest activity. Against this background, we functionally screened for novel metastasis modulators using a barcoded shRNA library and an orthotopic lung cancer model. We identified aryl hydrocarbon receptor (AHR), a sensor of xenobiotic chemicals and transcription factor, as suppressor of lung cancer metastasis. Knockdown of endogenous AHR induces epithelial–mesenchymal transition signatures, increases invasiveness of lung cancer cells in vitro and metastasis formation in vivo. Low intratumoral AHR expression associates with inferior outcome of patients with resected lung adenocarcinomas. Mechanistically, AHR triggers ATF4 signaling and represses matrix metalloproteinase activity, both counteracting metastatic programs. These findings link the xenobiotic defense system with control of lung cancer progression. AHR-regulated pathways are promising targets for innovative anti-metastatic strategies.

S6K1 blockade overcomes acquired resistance to EGFR-TKIs in non-small cell lung cancer.

The development of resistance to EGFR Tyrosine kinase inhibitors (TKIs) in NSCLC with activating EGFR mutations is a critical limitation of this therapy. In addition to genetic alterations such as EGFR secondary mutation causing EGFR-TKI resistance, compensatory activation of signaling pathways without interruption of genome integrity remains to be defined. In this study, we identified S6K1/MDM2 signaling axis as a novel bypass mechanism for the development of EGFR-TKI resistance. The observation of S6K1 as a candidate mechanism for resistance to EGFR TKI therapy was investigated by interrogation of public databases and a clinical cohort to establish S6K1 expression as a prognostic/predictive biomarker. The role of S6K1 in TKI resistance was determined in in vitro gain-and-loss of function studies and confirmed in subcutaneous and orthotopic mouse lung cancer models. Blockade of S6K1 by a specific inhibitor PF-4708671 synergistically enhanced the efficacy of TKI without showing toxicity. The mechanistic study showed the inhibition of EGFR caused nuclear translocation of S6K1 for binding with MDM2 in resistant cells. MDM2 is a downstream effector of S6K1-mediated TKI resistance. Taken together, we present evidence for the reversal of resistance to EGFR TKI by the addition of small molecule S6K1/MDM2 antagonists that could have clinical benefit.

Development of syngeneic murine cell lines for use in immunocompetent orthotopic lung cancer models

BackgroundImmunocompetent 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.MethodsPrimary 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.ResultsWe 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.ConclusionsThese 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.

Tranilast Inhibits TGF-β1-induced Epithelial-mesenchymal Transition and Invasion/Metastasis via the Suppression of Smad4 in Human Lung Cancer Cell Lines.

Transforming growth factor β1 (TGF-β1) is an important epithelial-mesenchymal transition (EMT) activator that regulates the expression of E-cadherin and vimentin through Smad signalling. Tranilast is an anti-allergic drug that inhibits TGF-β1, and is used in the treatment of keloids and hypertrophic scars. We investigated whether tranilast inhibits TGF-β1-induced EMT and invasiveness in human non-small cell lung cancer cell lines. We examined the effects of tranilast treatment on EMT markers, TGF-β1/Smad signalling, and cell invasiveness in A549 and PC14 cells. Tumours from a mouse orthotopic lung cancer model with or without tranilast treatment were also immunohistochemically evaluated. Tranilast increased E-cadherin expression via Smad4 suppression and inhibited cell invasion in TGF-β1-stimulated cells. Tranilast treatment of the in vivo mouse model reduced the pleural dissemination of cancer cells and suppressed vimentin and Smad4 expression. Tranilast inhibited TGF-β1-induced EMT and cellular invasion/metastasis by suppressing Smad4 expression in cancer cells.