Cancer is a leading cause of mortality throughout the world and new treatments are urgently needed. Recent studies suggest that bone marrow-derived mesenchymal stem cells (MSC) home to and incorporate within tumor tissue. We hypothesized that MSCs engineered to produce and deliver tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a transmembrane protein that causes selective apoptosis of tumor cells, would home to and kill cancer cells in a lung metastatic cancer model. Human MSCs were transduced with TRAIL and the IRES-eGFP reporter gene under the control of a tetracycline promoter using a lentiviral vector. Transduced and activated MSCs caused lung (A549), breast (MDAMB231), squamous (H357), and cervical (Hela) cancer cell apoptosis and death in coculture experiments. Subcutaneous xenograft experiments confirmed that directly delivered TRAIL-expressing MSCs were able to significantly reduce tumor growth [0.12 cm 3 (0.04-0.21) versus 0.66 cm 3 (0.21-1.11); P < 0.001]. We then found, using a pulmonary metastasis model, systemically delivered MSCs localized to lung metastases and the controlled local delivery of TRAIL completely cleared the metastatic disease in 38% of mice compared with 0% of controls (P < 0.05). This is the first study to show a significant reduction in metastatic tumor burden with frequent eradication of metastases using inducible TRAIL-expressing MSCs. This has a wide potential therapeutic role, which includes the treatment of both primary tumors and their metastases, possibly as an adjuvant therapy in clearing micrometastatic disease following primary tumor resection. [Cancer Res 2009;69(10):4134-42]

Sequencing data have been deposited at the European Genome-Phenome Archive (http://www.ebi.ac.uk/ega/) under accession numbers EGAD00001005193. Somatic mutation calls, including single base substitutions, indels and structural variants, from all 632 samples have been deposited on Mendeley Data with the identifier: http://dx.doi.org/10.17632/b53h2kwpyy.2. Code Availability Detailed method and custom R scripts for the analysis of mutational burden in bronchial epithelium are available in Supplementary Code. Other packages used in the analysis are listed below:

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Background Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has emerged as an important tool for the diagnosis and staging of lung cancer but its role in the diagnosis of tuberculous intrathoracic lymphadenopathy has not been established. The aim of this study was to describe the diagnostic utility of EBUS-TBNA in patients with intrathoracic lymphadenopathy due to tuberculosis (TB). Methods 156 consecutive patients with isolated intrathoracic TB lymphadenitis were studied across four centres over a 2-year period. Only patients with a confirmed diagnosis or unequivocal clinical and radiological response to antituberculous treatment during follow-up for a minimum of 6 months were included. All patients underwent routine clinical assessment and a CT scan prior to EBUS-TBNA. Demographic data, HIV status, pathological findings and microbiological results were recorded. Results EBUS-TBNA was diagnostic of TB in 146 patients (94%; 95% CI 88% to 97%). Pathological findings were consistent with TB in 134 patients (86%). Microbiological investigations yielded a positive culture of TB in 74 patients (47%) with a median time to positive culture of 16 days (range 3e84) and identified eight drug-resistant cases (5%). Ten patients (6%) did not have a specific diagnosis following EBUS; four underwent mediastinoscopy which confirmed the diagnosis of TB while six responded to empirical antituberculous therapy. There was one complication requiring an inpatient admission. Conclusions EBUS-TBNA is a safe and effective firstline investigation in patients with tuberculous intrathoracic lymphadenopathy.

Although integrins are known to mediate invasion and metastasis, recent studies reveal new ways in which they contribute to squamous-cell carcinoma. Integrin mutation or upregulation can expand the tumour stem-cell compartment by inhibiting differentiation or apoptosis. Integrins that are expressed by differentiated cells can stimulate or inhibit the proliferation of neighbouring tumour stem cells. These findings provide a mechanistic basis for the well-established links between altered integrin expression and tumour prognosis.

Murine mesenchymal stem cells are capable of differentiation into multiple cell types both in vitro and in vivo and may be good candidates to use as cell therapy for diseased or damaged organs. We have previously reported a method of enriching a population of murine MSCs that demonstrated a diverse differentiation potential both in vitro and in vivo. In this study, we show that this enriched population of murine mesenchymal stem cells embolize within lung capillaries following systemic injection and then rapidly expand within, and invade into, the lung parenchyma, forming tumor nodules. These lesions rarely contain cells bearing the immunohistochemical characteristics of lung epithelium, but they do show the characteristics of immature bone and cartilage that resembles exuberant fracture callus or well-differentiated osteosarcoma. Our findings indicate that murine mesenchymal stem cells can behave in a manner similar to tumor cells, with dysregulated growth and aberrant differentiation within the alveolar microenvironment after four passages. We demonstrate that unlike human MSCs, MSCs from different mouse strains can acquire chromosomal abnormalities after only a few in vitro passages. Moreover, other parameters, such as mouse strain used, might also play a role in the induction of these tumors. These findings might be clinically relevant for future stem cell therapy studies. STEM CELLS 2007;25:1586 -1594 Disclosure of potential conflicts of interest is found at the end of this article.

The ability of mesenchymal stem cells (MSC) to specifically home to tumors has suggested their potential use as a delivery vehicle for cancer therapeutics. MSC integration into tumors has been shown in animal models using histopathologic techniques after animal sacrifice. Tracking the delivery and engraftment of MSCs into human tumors will need in vivo imaging techniques. We hypothesized that labeling MSCs with iron oxide nanoparticles would enable in vivo tracking with magnetic resonance imaging (MRI). Human MSCs were labeled in vitro with superparamagnetic iron oxide nanoparticles, with no effect on differentiation potential, proliferation, survival, or migration of the cells. In initial experiments, we showed that as few as 1,000 MSCs carrying iron oxide nanoparticles can be detected by MRI one month after their coinjection with breast cancer cells that formed subcutaneous tumors. Subsequently, we show that i.v.-injected iron-labeled MSCs could be tracked in vivo to multiple lung metastases using MRI, observations that were confirmed histologically. This is the first study to use MRI to track MSCs to lung metastases in vivo. This technique has the potential to show MSC integration into human tumors, allowing early-phase clinical studies examining MSC homing in patients with metastatic tumors. [Cancer Res 2009;69(23):8862-7]

Many common diseases of the gas exchange surface of the lung have no specific treatment but cause serious morbidity and mortality. Idiopathic Pulmonary Fibrosis (IPF) is characterized by alveolar epithelial cell injury, interstitial inflammation, fibroblast proliferation and collagen accumulation within the lung parenchyma. Keratinocyte Growth Factor (KGF, also known as FGF-7) is a critical mediator of pulmonary epithelial repair through stimulation of epithelial cell proliferation. During repair, the lung not only uses resident cells after injury but also recruits circulating bone marrow-derived cells (BMDC). Several groups have used Mesenchymal Stromal Cells (MSCs) as therapeutic vectors, but little is known about the potential of Hematopoietic Stem cells (HSCs). Using an inducible lentiviral vector (Tet-On) expressing KGF, we were able to efficiently transduce both MSCs and HSCs, and demonstrated that KGF expression is induced in a regulated manner both in vitro and in vivo. We used the in vivo bleomycin-induced lung fibrosis model to assess the potential therapeutic effect of MSCs and HSCs. While both populations reduced the collagen accumulation associated with bleomycin-induced lung fibrosis, only transplantation of transduced HSCs greatly attenuated the histological damage. Using double immunohistochemistry, we show that the reduced lung damage likely occurs through endogenous type II pneumocyte proliferation induced by KGF. Taken together, our data indicates that bone marrow transplantation of lentivirus-transduced HSCs can attenuate lung damage, and shows for the first time the potential of using an inducible Tet-On system for cell based gene therapy in the lung.