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  • 1
    Abstract: Purpose: Tamoxifen remains an important hormonal therapy for ER-positive breast cancer; however, development of resistance is a major obstacle in clinics. Here, we aimed to identify novel mechanisms of tamoxifen resistance and provide actionable drug targets overcoming resistance.Experimental Design: Whole-transcriptome sequencing, downstream pathway analysis, and drug repositioning approaches were used to identify novel modulators [here: phosphodiesterase 4D (PDE4D)] of tamoxifen resistance. Clinical data involving tamoxifen-treated patients with ER-positive breast cancer were used to assess the impact of PDE4D in tamoxifen resistance. Tamoxifen sensitization role of PDE4D was tested in vitro and in vivo Cytobiology, biochemistry, and functional genomics tools were used to elucidate the mechanisms of PDE4D-mediated tamoxifen resistance.Results: PDE4D, which hydrolyzes cyclic AMP (cAMP), was significantly overexpressed in both MCF-7 and T47D tamoxifen-resistant (TamR) cells. Higher PDE4D expression predicted worse survival in tamoxifen-treated patients with breast cancer (n = 469, P = 0.0036 for DMFS; n = 561, P = 0.0229 for RFS) and remained an independent prognostic factor for RFS in multivariate analysis (n = 132, P = 0.049). Inhibition of PDE4D by either siRNAs or pharmacologic inhibitors (dipyridamole and Gebr-7b) restored tamoxifen sensitivity. Sensitization to tamoxifen is achieved via cAMP-mediated induction of unfolded protein response/ER stress pathway leading to activation of p38/JNK signaling and apoptosis. Remarkably, acetylsalicylic acid (aspirin) was predicted to be a tamoxifen sensitizer using a drug repositioning approach and was shown to reverse resistance by targeting PDE4D/cAMP/ER stress axis. Finally, combining PDE4D inhibitors and tamoxifen suppressed tumor growth better than individual groups in vivoConclusions: PDE4D plays a pivotal role in acquired tamoxifen resistance via blocking cAMP/ER stress/p38-JNK signaling and apoptosis. Clin Cancer Res; 24(8); 1987-2001. (c)2018 AACR.
    Type of Publication: Journal article published
    PubMed ID: 29386221
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  • 2
    Publication Date: 2018-04-14
    Description: Purpose: Tamoxifen remains an important hormonal therapy for ER-positive breast cancer; however, development of resistance is a major obstacle in clinics. Here, we aimed to identify novel mechanisms of tamoxifen resistance and provide actionable drug targets overcoming resistance. Experimental Design: Whole-transcriptome sequencing, downstream pathway analysis, and drug repositioning approaches were used to identify novel modulators [here: phosphodiesterase 4D (PDE4D)] of tamoxifen resistance. Clinical data involving tamoxifen-treated patients with ER-positive breast cancer were used to assess the impact of PDE4D in tamoxifen resistance. Tamoxifen sensitization role of PDE4D was tested in vitro and in vivo . Cytobiology, biochemistry, and functional genomics tools were used to elucidate the mechanisms of PDE4D-mediated tamoxifen resistance. Results: PDE4D, which hydrolyzes cyclic AMP (cAMP), was significantly overexpressed in both MCF-7 and T47D tamoxifen-resistant (TamR) cells. Higher PDE4D expression predicted worse survival in tamoxifen-treated patients with breast cancer ( n = 469, P = 0.0036 for DMFS; n = 561, P = 0.0229 for RFS) and remained an independent prognostic factor for RFS in multivariate analysis ( n = 132, P = 0.049). Inhibition of PDE4D by either siRNAs or pharmacologic inhibitors (dipyridamole and Gebr-7b) restored tamoxifen sensitivity. Sensitization to tamoxifen is achieved via cAMP-mediated induction of unfolded protein response/ER stress pathway leading to activation of p38/JNK signaling and apoptosis. Remarkably, acetylsalicylic acid (aspirin) was predicted to be a tamoxifen sensitizer using a drug repositioning approach and was shown to reverse resistance by targeting PDE4D/cAMP/ER stress axis. Finally, combining PDE4D inhibitors and tamoxifen suppressed tumor growth better than individual groups in vivo . Conclusions: PDE4D plays a pivotal role in acquired tamoxifen resistance via blocking cAMP/ER stress/p38-JNK signaling and apoptosis. Clin Cancer Res; 24(8); 1987–2001. ©2018 AACR .
    Print ISSN: 1078-0432
    Electronic ISSN: 1557-3265
    Topics: Medicine
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  • 3
    Publication Date: 2015-10-24
    Description: The immune system plays an important role in regulating tumor growth and metastasis. Classical monocytes promote tumorigenesis and cancer metastasis, but how nonclassical "patrolling" monocytes (PMo) interact with tumors is unknown. Here we show that PMo are enriched in the microvasculature of the lung and reduce tumor metastasis to lung in multiple mouse metastatic tumor models. Nr4a1-deficient mice, which specifically lack PMo, showed increased lung metastasis in vivo. Transfer of Nr4a1-proficient PMo into Nr4a1-deficient mice prevented tumor invasion in the lung. PMo established early interactions with metastasizing tumor cells, scavenged tumor material from the lung vasculature, and promoted natural killer cell recruitment and activation. Thus, PMo contribute to cancer immunosurveillance and may be targets for cancer immunotherapy.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hanna, Richard N -- Cekic, Caglar -- Sag, Duygu -- Tacke, Robert -- Thomas, Graham D -- Nowyhed, Heba -- Herrley, Erica -- Rasquinha, Nicole -- McArdle, Sara -- Wu, Runpei -- Peluso, Esther -- Metzger, Daniel -- Ichinose, Hiroshi -- Shaked, Iftach -- Chodaczek, Grzegorz -- Biswas, Subhra K -- Hedrick, Catherine C -- F32 HL117533-02/HL/NHLBI NIH HHS/ -- R01 CA202987/CA/NCI NIH HHS/ -- R01 HL118765/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 2015 Nov 20;350(6263):985-90. doi: 10.1126/science.aac9407. Epub 2015 Oct 22.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA. rhanna@lji.org hedrick@lji.org. ; Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey. ; Izmir Biomedicine and Genome Center, Dokuz Eylul University, Izmir, Turkey. ; Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA. ; Microscopy Core, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA. ; Department of Functional Genomics and Cancer, Institut de Genetique et de Biologie Moleculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR 7104, Universite de Strasbourg, Illkirch, France. ; Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Japan. ; Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26494174" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Immunologic Surveillance/*immunology ; Immunotherapy/methods ; Killer Cells, Natural/immunology ; Lung Neoplasms/*immunology/*secondary/therapy ; Mice ; Mice, Mutant Strains ; Monocytes/*immunology ; Neoplasm Invasiveness ; Neoplasm Metastasis ; Neoplasms, Experimental/immunology/secondary ; Nuclear Receptor Subfamily 4, Group A, Member 1/genetics
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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