The mature bone morphogenetic protein-2 is aberrantly expressed in non-small cell lung carcinomas and stimulates tumor growth of A549 cells

To help identify genes, which may regulate metastasis in lung cancer, we performed representational difference analysis between a patient-derived non-small cell lung carcinoma (NSCLC) and immortalized normal human bronchial epithelial cells. This analysis revealed that bone morphogenetic proteins-2/4 (BMP) mRNA was expressed in the lung carcinoma. BMP-2/4 are known to induce pluripotent cell differentiation, enhance cell migration and stimulate proliferation during embryonic development. Despite being powerful morphogens it is not known whether BMP-2/4 have significant biological activity in human carcinomas. Furthermore, it has not been established whether the mature active BMP-2/4 protein is aberrantly expressed in patient-derived tumors. The purpose of this study was to determine whether the expression of the mature BMP-2/4 protein is disregulated in human lung carcinomas and to establish whether it has adverse biological activity. This study reveals that the mature BMP-2 protein, but not BMP-4, is highly over-expressed in human NCSLC with little to no expression in normal lung tissue or benign lung tumors. The expression of BMP-2 localized specifically to the cancer cells. Recombinant BMP-2 stimulated in vitro, the migration and invasiveness of the A549 and H7249 human lung cancer cell lines. In vivo, recombinant BMP-2 enhanced the growth of tumors formed from A549 cells injected subcutaneously into nude mice. Furthermore, inhibition of BMP-2 activity with either recombinant noggin or anti-BMP-2 antibody resulted in a significant reduction in tumor growth. This study shows that expression of the mature BMP-2 protein is disregulated in the majority of NSCLC. BMP-2 enhancement of tumor cell migration and invasion, as well as stimulating tumor growth in vivo, suggests it has important biological activity in lung carcinomas.     

Inhibition of nuclear factor kappaB induces apoptosis following treatment with tumor necrosis factor alpha and an antioxidant in human prostate cancer cells

Transforming growth factor beta-1 (TGFbeta-1) and tumor necrosis factor alpha (TNF-alpha), an activator of nuclear factor kappa B (NF-kappaB), modulate apoptosis and/or cell growth. This study was designed to investigate the activity of NF-kappaB and its regulation of inhibitor of apoptosis gene (c-IAP2) in two human prostate cancer cell lines, DU-145 (which is androgen unresponsive) and ALVA-101 (which is moderately androgen responsive). These cells were treated with and without various concentrations of a strong antioxidant, pyrrolidinedithiocarbamate (PDTC), and TNF-alpha at various time intervals. Following treatments, cell growth and apoptosis were determined by ELISA techniques. NF-kappaB activity was determined by electrophoretic mobility shift assay (EMSA), and c-IAP2 mRNA production was determined with Northern blot analysis. PDTC treatment significantly reduced cell growth up to 80% in both DU-145 and ALVA-101 cells. TNF-alpha and lower but not higher doses of PDTC combined demonstrated an additive inhibition of cell growth in both cell lines. Active NF-kappaB and c-IAP2 was blocked significantly following PDTC treatments, whereas treatments with TNF-alpha alone showed increased NF-kappaB activity and c-IAP2. However, when both PDTC and TNF-alpha were combined, nuclear presence of NF-kappaB and c-IAP2 were reduced significantly (P < 0.05) to levels observed with PDTC alone. In conclusion, the antioxidant, PDTC, appears to initiate apoptosis by blocking cytoplasmic NF-kappaB translocation to the nucleus where it normally activates the production of apoptosis-inhibitory proteins like c-IAP2. Both TNF-alpha and PDTC alone cause apoptosis and reduce cell growth, but their combined effects are additive in reducing cell growth of DU-145 and ALVA-101 human prostate cancer cells.     

Apoptotic responsiveness of PC-3 prostate cancer cells to tumor necrosis factor-related apoptosis-inducing ligand: evidence for differential effects of Bcl-xL and Bcl-2 down-regulation

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is cytotoxic to the majority of cancer cells while sparing most normal cells. However, different prostate carcinoma cell lines respond with different sensitivities to TRAIL, urging us to disclose the mechanisms that determine TRAIL sensitivity in prostate cancer cells, i.e. to identify and validate target molecules. In this report, we show that down-regulation ('knockdown') of Bcl-xL, but not Bcl-2, markedly amplifies TRAIL-induced apoptosis in PC-3 prostate carcinoma cells. The knockdown was accomplished by second-generation chimeric antisense oligonucleotides: Bcl-2 and Bcl-xL levels were strongly and reproducibly reduced, as revealed by real-time RT-PCR and Western blot analyses. Knockdown of Bcl-xL and administration of TRAIL significantly synergized in dissipation of mitochondrial membrane potential, release of cytochrome c, activation of caspase-9 and -3 and, consequently, apoptotic cell death. Knockdown of Bcl-2 did not affect any of these activities. We conclude that that Bcl-xL represents a promising target to improve cancer therapy by potentiating TRAIL's cytotoxic effects.     

Functional roles of tumor necrosis factor‐related apoptosis‐inducing ligand–DR5 interaction in B16F10 cells by activating the nuclear factor‐κB pathway to induce metastatic potential

Tumor necrosis factor‐related apoptosis‐inducing ligand (TRAIL) has been recognized as a promising target for cancer therapy because it can induce apoptotic cell death in tumor cells but not normal cells. Although TRAIL shows specific tumoricidal activity, resistance to TRAIL‐induced apoptosis in some tumor cells has been considered a clinical obstacle of its application. It has been shown that TRAIL provides inflammatory signals that may contribute to the TRAIL‐resistance of cancer cells; however, it is not known whether TRAIL itself is involved in malignant cancer cell behavior. In the present study, we examined the functional role of TRAIL in B16F10 mouse melanoma cells, which are totally insensitive to TRAIL‐induced apoptosis. By establishing B16F10 cells stably expressing the nuclear factor‐κB (NFκB)‐luciferase reporter gene, we found that TRAIL can activate NFκB through its death receptor DR5 in B16F10 cells. Furthermore, TRAIL–DR5 interaction not only promoted malignant behaviors of B16F10 cells, such as cell proliferation and MMP‐9 production, but also induced lung metastasis of B16F10 cells in vivo. These findings may imply a contrary role for the TRAIL–DR5 pathway in the inflammatory tumor microenvironment, in its ability to induce the metastatic potential of B16F10 melanoma cells instead of inducing apoptosis.