15 research outputs found

    MUC1 alters oncogenic events and transcription in human breast cancer cells

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    INTRODUCTION: MUC1 is an oncoprotein whose overexpression correlates with aggressiveness of tumors and poor survival of cancer patients. Many of the oncogenic effects of MUC1 are believed to occur through interaction of its cytoplasmic tail with signaling molecules. As expected for a protein with oncogenic functions, MUC1 is linked to regulation of proliferation, apoptosis, invasion, and transcription. METHODS: To clarify the role of MUC1 in cancer, we transfected two breast cancer cell lines (MDA-MB-468 and BT-20) with small interfering (si)RNA directed against MUC1 and analyzed transcriptional responses and oncogenic events (proliferation, apoptosis and invasion). RESULTS: Transcription of several genes was altered after transfection of MUC1 siRNA, including decreased MAP2K1 (MEK1), JUN, PDGFA, CDC25A, VEGF and ITGAV (integrin α(v)), and increased TNF, RAF1, and MMP2. Additional changes were seen at the protein level, such as increased expression of c-Myc, heightened phosphorylation of AKT, and decreased activation of MEK1/2 and ERK1/2. These were correlated with cellular events, as MUC1 siRNA in the MDA-MB-468 line decreased proliferation and invasion, and increased stress-induced apoptosis. Intriguingly, BT-20 cells displayed similar levels of apoptosis regardless of siRNA, and actually increased proliferation after MUC1 siRNA. CONCLUSION: These results further the growing knowledge of the role of MUC1 in transcription, and suggest that the regulation of MUC1 in breast cancer may be more complex than previously appreciated. The differences between these two cell lines emphasize the importance of understanding the context of cell-specific signaling events when analyzing the oncogenic functions of MUC1, and caution against generalizing the results of individual cell lines without adequate confirmation in intact biological systems

    Probing heteronuclear N-15-O-17 and C-13-O-17 connectivities and proximities by solid-state NMR spectroscopy

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    Heteronuclear solid-state magic-angle spinning (MAS) NMR experiments for probing N-15-O-17 dipolar and J couplings are presented for [H-2(NH3),1-C-13,N-15,O-17(2)]glycine center dot(HCl)-H-2 and [N-15(2), O-17(2)]uracil. Two-dimensional N-15-O-17 correlation spectra are obtained using the R-3-HMQC experiment; for glycine center dot(HCl)-H-2, the intensity of the resolved peaks for the C=O and C-(OH)-H-2 O-17 resonances corresponds to the relative magnitude of the respective N-15-O-17 dipolar couplings. O-17-N-15 REDOR curves are presented for glycine center dot(HCl)-H-2; fits of the initial buildup (Delta S/S < 0.2) yield effective dipolar couplings in agreement with (+/- 20%) the root-sum-squared dipolar couplings determined from the crystal structure. Experimental N-15-O-17 REAPDOR curves for the N-15 resonances in glycine center dot(HCl)-H-2 and uracil fit well to the universal curve presented by Goldbourt et al. (J. Am. Chem. Soc. 2003, 125,11194). Heteronuclear C-13-O-17 and N-15-O-17 J couplings were experimentally determined from fits of the quotient of the integrated intensity obtained in a heteronuclear and a homonuclear spin-echo experiment, S-Q(tau) = S-HET(tau)/S-HOM(tau). For glycine center dot(HCl)-H-2, (1)J(CO) was determined as 24.7 +/- 0.2 and 25.3 +/- 0.3 Hz for the C=O and C-(OH)-H-2 resonances, respectively, while for uracil, the average of the two NH center dot center dot center dot O hydrogen-bond-mediated J couplings was determined as 5.1 +/- 0.6 Hz. In addition, two-bond intramolecular J couplings, (2)J(OO) = 8.8 +/- 0.9 Hz and (2)J(N1,N3) = 2.7 +/- 0.1 Hz, were determined for glycine center dot(HCl)-H-2 and uracil, respectively. Excellent agreement was found with J couplings calculated using the CASTEP code using geometrically optimized crystal structures for glycine center dot HCl [(1)J(CO)(C=O) = 24.9 Hz, (1)J(CO)(C-OH) = 27.5 H Z, (2)J(OO) = 7.9 Hz] and uracil [(2h)J(N1,O4) = 6.1 Hz, (2h)J(N3,O4) = 4.6 Hz, (2)J(N1,N3) = 2.7 Hz]

    Safety and efficacy of BAY1436032 in IDH1-mutant AML: phase I study results

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    The mutant IDH1 (mIDH1) inhibitor BAY1436032 demonstrated robust activity in preclinical AML models, supporting clinical evaluation. In the current dose-escalation study, BAY1436032 was orally administered to 27 mIDH1 AML subjects across 4 doses ranging from 300 to 1500 mg twice-daily. BAY1436032 exhibited a relatively short half-life and apparent non-linear pharmacokinetics after continuous dosing. Most subjects experienced only partial target inhibition as indicated by plasma R-2HG levels. BAY1436032 was safe and a maximum tolerated dose was not identified. The median treatment duration for all subjects was 3.0 months (0.49-8.5). The overall response rate was 15% (4/27; 1 CRp, 1 PR, 2 MLFS), with responding subjects experiencing a median treatment duration of 6.0 months (3.9-8.5) and robust R-2HG decreases. Thirty percent (8/27) achieved SD, with a median treatment duration of 5.5 months (3.1-7.0). Degree of R-2HG inhibition and clinical benefit did not correlate with dose. Although BAY1436032 was safe and modestly effective as monotherapy, the low overall response rate and incomplete target inhibition achieved at even the highest dose tested do not support further clinical development of this investigational agent in AML
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