Metastatic Lung Cell Research Articles

Peroxiredoxin 2 specifically regulates the oxidative and metabolic stress response of human metastatic breast cancer cells in lungs

Little is known about metastatic pathways that are specific to the lung rather than other organs. We previously showed that antioxidant proteins such as peroxiredoxins were specifically upregulated in lung metastatic breast cancer cells. We hypothesize that cancer cells that live under aerobic conditions, as might be the case in lungs, protect themselves against the damage caused by reactive oxygen species (ROS). To examine this hypothesis, we studied the role of peroxiredoxin-2 (PRDX2) in lung vs bone metastasis formation. A metastatic variant of MDA-MB-435 breast cancer cells that specifically metastasize to lungs (435-L3) was transduced with short hairpin RNAs to specifically silence PRDX2. Conversely, a bone metastatic variant of MDA-MB-231 cells (BO2) was stably transfected to overexpress PRDX2. The 435-L3 cells silenced for PRDX2 were significantly more sensitive to H(2)O(2)-induced oxidative stress than the parental and scrambled transfected cells. BO2/PRDX2 cells produced less ROS than BO2/green fluorescent protein control cells under oxidative stress. Moreover, PRDX2 knockdown inhibited the growth of 435-L3 cells in the lungs, whereas lymph node metastasis remained unaffected. In contrast, PRDX2 overexpression in bone metastatic BO2 breast cancer cells led to drastic inhibition of the skeletal tumor burden and reduction of bone destruction. Furthermore, PRDX2 expression in breast cancer cells was associated with a glucose-dependent phenotype, different from bone metastatic cells. Overall, our results strongly suggest that PRDX2 is a targetable 'metabolic adaptor' driver protein implicated in the selective growth of metastatic cells in the lungs by protecting them against oxidative stress.

Targeting of polymeric nanoparticles to lung metastases by surface-attachment of YIGSR peptide from laminin

Effective therapy for disseminated metastatic cancer is currently impossible because of low drug accumulation in target sites. Here, we aimed to enhance nanoparticle (NP) targeting to lung melanoma metastases via interactions with the laminin receptor, whose expression is upregulated in metastatic cells. To enable NP follow-up and a framework for targeting ligand binding, Estapor ® fluorescent NPs (299 ± 6 nm in diameter) with surface carboxylic groups were employed and the laminin receptor binding peptide (YIGSR) was attached to their surface to facilitate targeting. In vitro uptake studies performed under medium flow conditions revealed that the uptake of YIGSR-attached NPs by monolayers of B16 melanoma cells was 2-fold higher compared to the uptake of scrambled peptide-NPs. In cultures of healthy lung cells, the uptake of YIGSR-NPs was low and similar to the uptake of scrambled peptide-NPs. Competition assays using cultured B16 melanoma cells pre-incubated with soluble laminin confirmed that the entry of the YIGSR-modified NPs was mediated via interaction with the laminin receptor. Following intravenous (i.v.) administration into B16 melanoma tumor-bearing mice, targeting of the tumor by the YIGSR-NPs was up to five-fold higher than the scrambled peptide-NPs, with no heart, liver or lung tropism. In an experimental lung metastases model, following i.v. administration the YIGSR-NPs targeted the cancerous metastatic cells in lungs, with nearly no targeting to the healthy lung cells. Collectively, the data indicate that YIGSR-targeted NPs have a potential to be used for systemic delivery of chemotherapeutic drugs for the treatment of metastatic lung cancer.

Development of a three-dimensional model of lung cancer using cultured transformed lung cells

Despite great strides in understanding cancer biology, the role cellular differentiation and three-dimensional (3-D) structural organization play in metastasis and malignancy remains unclear. Development of 3-D cultures may ultimately provide a model facilitating discovery and interpretation of more relevant information for the expression and role of antibodies in lung cellular pathobiology. The purpose was to develop traditional monolayer (ML) and 3-D cultures of a known transformed metastatic lung cell line and then determine similarities and differences between cultures in terms of differentiation, molecular marker expression and metastasis. A transformed lung cell line (BZR-T33) was initially transfected with green fluorescent protein (GFP) in ML culture. Nude mice were inoculated with BZR-T33 and observed for metastasis. BZR-T33 was grown as ML and 3-D cultures under identical conditions. Immunohistochemical comparison for degree of antibody expression between cultures and control tissue were studied. Electron microscopy (EM) for identification of ultra structures was done and compared between cultures. A 3-D co-culture containing GFP-transformed cells over an immortalized lung-cell line was developed. The GFP-transfected cell line formed tumors and metastasized in mice. EM identified significant mitochondrial and granular endoplasmic reticular pathology in ML not seen in 3-D. Degree of differentiation shows ultra structures and antibody expressions were more representative of control tissue in 3-D than ML. The co-culture experiment in 3-D demonstrates the ability of transformed cells to penetrate the sub-layer of immortalized cells. Development of 3-D cultures will provide a new and powerful tool to study lung biology and pathobiology.