TMF/ARA160 is a Golgi-associated protein whose level is downregulated in solid tumors. TMF changes its subcellular localization on exposure of cells to stress cues, thereby, directing proteins, such as the key transcription factor, Stat3, to proteasomal degradation. Here, we show that enforced ectopic expression of HA-TMF in PC3 prostate carcinoma cells, which do not express Stat3, significantly attenuated the development and growth of xenograft tumors elicited by these cells in athymic mice. Immunohistochemical analysis revealed impaired angiogenesis and accelerated onset of apoptosis in the HA-TMF-expressing tumors. RNA expression profiling revealed the downregulation of several proangiogenic genes in HA-TMF-expressing xenografts. Among these were the interleukin-8 and interleukin-1b genes, whose expression is controlled by nuclear factor-kB. The level of the nuclear factor-kB component, p65/RelA, was decreased in HA-TMF-expressing xenografts, and TMF was found to direct the ubiquitination and proteasomal degradation of p65/RelA in metabolically stressed PC3 clones. Taken together, our findings indicate that TMF/ ARA160 is a regulator of key transcription factors under metabolic constraints, thereby affecting angiogenesis and progression of solid tumors, which are subjected to metabolic stress. ' UICCAs solid tumors expand, they can rapidly outgrow the carrying capacity of the local vasculature. Tumors are, therefore, often filled with areas, characterized by lowered oxygen content, or hypoxia, and limited nutrient supply.

We herein describe a novel protein encoded by a single exon in a single-copy conserved mammalian gene. This protein, termed TMF regulated nuclear protein (TRNP), was identified in a yeast "two-hybrid" screen in which the "BC box" containing protein-TMF/ARA160 served as a bait. TRNP is a basic protein which accumulates in an insoluble nuclear fraction in mammalian cells. It is 227 aa long in humans and chimps and 223 aa long in mice. Enforced expression of TRNP in cells that do not express this protein significantly increased their proliferation rate by enhancing their cell-cycle progression from the G0/G1 to the S phase. Like another proliferation promoting factor, Stat3, TRNP was directed to proteasomal degradation by TMF/ ARA160. Thus, the trnp gene encodes a novel mammalian conserved nuclear protein that can accelerate cellcycle progression and is regulated by TMF/ARA160.

The plant Inula viscosa has been shown to possess many important medicinal benefits, including anti-inflammatory, anti-oxidant, anti-bacterial, and anti-fungal activities, but the plant metabolites that mediate these effects and their mechanism of action are poorly understood. In a previous study, we demonstrated a reduced expression of the p65 subunit of nuclear factor kappa B (NFκB) in melanoma cells treated with the purified sesquiterpene lactone compounds, Inuviscolide (Inv) and Tomentosin (Tom), extracted from Inula viscosa leaves. In this study, we tested the invitro effect of these purified compounds on the secretion of pro-inflammatory cytokines from human peripheral blood mononuclear cells (PBMCs) upon stimulation with lipopolysaccharide (LPS) or phorbol myristate acetate (PMA). Their possible mechanism of action was also studied. The results showed that both agents caused decreased production of IL-2, IL-1β, IFNγ, and slightly increased secretion of TNFα, whereas secretion of IL-6 was not affected. The elevated levels of TNFα did not appear to affect the viability of human PBMCs. Western blot analysis revealed a reduction in the protein level of both the transcription factor component p65/RelA of nuclear factor-κB (NFκB) and the signal transducer and activator of transcription 1 (STAT1) through proteosomal degradation. However, no change was observed in the expression level of the nuclear factor-κB component, p50 (NFκB), or the signal transducer and activator of transcription 3 (STAT3). Taken together, our results indicate the possible future use of these agents as an anti-inflammatory treatment in cases where overstimulation of cytokine secretion is the basis for the pathological symptoms.