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  • br Inhibition of the AR in prostate cancer may

    2020-07-29


    Inhibition of the AR in prostate cancer may contribute the most to malignant transformation and tumors progressing to CRPC [56–58]. We demonstrated a role of the ZBTB46 protein for the NE transformation of prostate cancer and identified ZBTB46 as a novel effector of aberrant AR signaling. A key mechanistic requirement of our findings was the role of ZBTB46 in crosstalk with AR inhibition leading to NEPC dif-ferentiation and inflammation-associated gene expression. We demon-strated that ZBTB46 Pifithrin-α (PFTα) is associated with features of NEPC and regulates the expression of PTGS1. We demonstrated that this pathway involves ZBTB46 activation of an antagonist AR program, resulting in NEPC differentiation and the abundance of PTGS1 stimulation in prostate cancer patients with ADT resistance. Our results highlight the role of ZBTB46 in prostate NE transdifferentiation, supporting a model of progressive reprogramming of prostate cancer after ADT.
    We elucidated the effect of an anti-inflammatory drug on inducing sensitivity to anti-AR signaling therapy by inhibiting PTGS1. Although we demonstrated that PTGS1 is a direct target of ZBTB46, our results showed that the combination of MDV3100 and a PTGS1 inhibitor can also reduce ZBTB46, suggesting a positive feedback loop between ZBTB46 and PTGS1 or inflammation signaling. An earlier study showed that inflammation signaling is involved in resistance to AR antagonists [30], and we also showed that targeting AR activity induces both ZBTB46 and PTGS1; it is possible that the downstream inflammation signaling of PTGS1 is also involved in the androgen-resistant pheno-type, partly through the induction of ZBTB46.
    In summary, this study identified a novel molecular determinant of NEPC differentiation, uncovering a broad oncogenic role for the ZBTB46 protein in tumor cell proliferation and malignancy coupled with PTGS1 expression. Our results support a model whereby SPDEF possibly functions as a transcriptional factor to invert the oncogenic role of ZBTB46, promoting NEPC differentiation. In addition, ZBTB46 inhibition may cause inactivation of the ZBTB46-associated in-flammatory response proteins, signaling pathway components that af-fect the biological functions of NEPC cells. Therefore, ZBTB46 is a po-tential diagnostic marker and therapeutic target in combination with anti-inflammatory drugs in a subset of NEPC patients after ADT.
    Authors’ contributions
    W.Y. Chen and Y.N. Liu designed the experiments and supervised the project. W.Y. Chen, K. C. Jiang, and W.H. Chen performed the ex-periments. Y.C. Wen, T. Zeng, and J. Huang provided the human prostate cancer samples. W.Y. Chen and Q. Zheng performed the his-tomorphometric analysis. H.L. Yeh constructed the databases and per-formed the statistical and bioinformatics analyses. All authors analyzed and interpreted the data. W.Y. Chen, T. Zeng, and Y.N. Liu wrote, 
    reviewed, and/or revised the manuscript.
    Conflicts of interest
    The authors declare no potential conflicts of interest.
    Acknowledgments
    This work was jointly supported by grants from the Ministry of Science and Technology of Taiwan (MOST105-2628-B-038-006-MY3 and MOST107-2628-B-038-001 to Y.N. Liu, and MOST107-2320-B-038-058 to W.Y. Chen), Taipei Medical University-Wan Fang Hospital (107TMU-WFH-03 to W.Y. Chen), and the National Health Research Institute of Taiwan (NHRI-EX107-10702BI to Y.N. Liu). This work was also financially supported by the “TMU Research Center of Cancer Translational Medicine” from The Featured Areas Research Center Program within the framework of the Higher Education Sprout Project by the Ministry of Education (MOE) in Taiwan.
    Appendix A. Supplementary data
    References
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