Interaction of ZPR1 with Translation Elongation Factor-1α in Proliferating Cells

The zinc finger protein ZPR1 is present in the cytoplasm of quiescent mammalian cells and translocates to the nucleus upon treatment with mitogens, including epidermal growth factor (EGF). Homologues of ZPR1 were identified in yeast and mammals. These ZPR1 proteins bind to eukaryotic translation elongation factor-1α (eEF-1α). Studies of mammalian cells demonstrated that EGF treatment induces the interaction of ZPR1 with eEF-1α and the redistribution of both proteins to the nucleus. In the yeast Saccharomyces cerevisiae, genetic analysis demonstrated that ZPR1 is an essential gene. Deletion analysis demonstrated that the NH2-terminal region of ZPR1 is required for normal growth and that the COOH-terminal region was essential for viability in S. cerevisiae. The yeast ZPR1 protein redistributes from the cytoplasm to the nucleus in response to nutrient stimulation. Disruption of the binding of ZPR1 to eEF-1α by mutational analysis resulted in an accumulation of cells in the G2/M phase of cell cycle and defective growth. Reconstitution of the ZPR1 interaction with eEF-1α restored normal growth. We conclude that ZPR1 is essential for cell viability and that its interaction with eEF-1α contributes to normal cellular proliferation

The cytoplasmic zinc finger protein ZPR1 accumulates in the nucleolus of proliferating cells

The zinc finger protein ZPR1 translocates from the cytoplasm to the nucleus after treatment of cells with mitogens. The function of nuclear ZPR1 has not been defined. Here we demonstrate that ZPR1 accumulates in the nucleolus of proliferating cells. The role of ZPR1 was examined using a gene disruption strategy. Cells lacking ZPR1 are not viable. Biochemical analysis demonstrated that the loss of ZPR1 caused disruption of nucleolar function, including preribosomal RNA expression. These data establish ZPR1 as an essential protein that is required for normal nucleolar function in proliferating cells

M402, a Novel Heparan Sulfate Mimetic, Targets Multiple Pathways Implicated in Tumor Progression and Metastasis

Heparan sulfate proteoglycans (HSPGs) play a key role in shaping the tumor microenvironment by presenting growth factors, cytokines, and other soluble factors that are critical for host cell recruitment and activation, as well as promoting tumor progression, metastasis, and survival. M402 is a rationally engineered, non-cytotoxic heparan sulfate (HS) mimetic, designed to inhibit multiple factors implicated in tumor-host cell interactions, including VEGF, FGF2, SDF-1α, P-selectin, and heparanase. A single s.c. dose of M402 effectively inhibited seeding of B16F10 murine melanoma cells to the lung in an experimental metastasis model. Fluorescent-labeled M402 demonstrated selective accumulation in the primary tumor. Immunohistological analyses of the primary tumor revealed a decrease in microvessel density in M402 treated animals, suggesting anti-angiogenesis to be one of the mechanisms involved in-vivo. M402 treatment also normalized circulating levels of myeloid derived suppressor cells in tumor bearing mice. Chronic administration of M402, alone or in combination with cisplatin or docetaxel, inhibited spontaneous metastasis and prolonged survival in an orthotopic 4T1 murine mammary carcinoma model. These data demonstrate that modulating HSPG biology represents a novel approach to target multiple factors involved in tumor progression and metastasis

Synthesis and Biological Evaluation of a Unique Heparin Mimetic Hexasaccharide for Structure–Activity Relationship Studies

To date, the structure–activity relationship studies of heparin/heparan sulfate with their diverse binding partners such as growth factors, cytokines, chemokines, and extracellular matrix proteins have been limited yet provide early insight that specific sequences contribute to this manifold biological role. This has led to an impetus for the chemical synthesis of oligosaccharide fragments of these complex polysaccharides, which can provide an effective tool for this goal. The synthesis of three heparin mimetic hexasaccharides with distinct structural patterns is described herein, and the influence of the targeted substitution on their bioactivity profiles is studied using <i>in vitro</i> affinity and/or inhibition toward different growth factors and proteins. Additionally, the particularly challenging synthesis of an irregular hexasaccharide is reported, which, interestingly, in spite of being considerably structurally similar with its two counterparts, displayed a unique and remarkably distinct profile in the test assays

M402 monotherapy or in combination with docetaxel shows survival benefits in the orthotopic murine mammary carcinoma 4T1 model.

<p>(A) Groups of female BALB/c mice (n = 20) were inoculated orthotopically with 1×10⁵ 4T1 cells in the 4th mammary fat pad on day 0. M402 treatment delivered by sc implanted osmotic pumps at 40 mg/kg/day started on day 1. Primary tumors were removed on day 10. Survival of the M402 treated group was significantly longer than that of the saline control group (P<0.02 by Log-Rank test). (B–D) Groups of female BALB/c mice (n = 16) were inoculated orthotopically with 5×10⁴ 4T1-luc2-1A4 cells in the 4th mammary fat pad on day 0. M402 treatment delivered by sc implanted osmotic pumps at 40 mg/kg/day started on day 1. Primary tumors were removed on day 10 by surgery. Weekly ip injection of saline or docetaxel (10 mg/kg) started on day 14. After primary tumor resection, animals were monitored twice weekly with bioluminescent imaging. (B) Whole body bioluminescence (Mean±SEM) quantified as photons/second over time. (C) Bioluminescence imaging of all the experimental animals on day 29. (D) Kaplan-Meier survival curve. Survival of the M402 and docetaxel combination group was significantly longer than that of the saline control and the docetaxel monotherapy group (P<0.0001 and P<0.05, respectively, by Log-Rank test).</p