Browsing by Author "Putt, Karson S."

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    A novel micellular fluorogenic substrate for quantitating the activity of 1-phosphatidylinositol 4,5-bisphosphate phosphodiesterase gamma (PLCγ) enzymes
    (Public Library of Science, 2024-03-29) Visvanathan, Ramya; Utsuki, Tadanobu; Beck, Daniel E.; Clayton, W. Brent; Lendy, Emma; Sun, Kuai-lin; Liu, Yinghui; Hering, Kirk W.; Mesecar, Andrew; Zhang, Zhong-Yin; Putt, Karson S.; Pharmacology and Toxicology, School of Medicine
    The activities of the phospholipase C gamma (PLCγ) 1 and 2 enzymes are essential for numerous cellular processes. Unsurprisingly, dysregulation of PLCγ1 or PLCγ2 activity is associated with multiple maladies including immune disorders, cancers, and neurodegenerative diseases. Therefore, the modulation of either of these two enzymes has been suggested as a therapeutic strategy to combat these diseases. To aid in the discovery of PLCγ family enzyme modulators that could be developed into therapeutic agents, we have synthesized a high-throughput screening-amenable micellular fluorogenic substrate called C16CF3-coumarin. Herein, the ability of PLCγ1 and PLCγ2 to enzymatically process C16CF3-coumarin was confirmed, the micellular assay conditions were optimized, and the kinetics of the reaction were determined. A proof-of-principle pilot screen of the Library of Pharmacologically Active Compounds 1280 (LOPAC1280) was performed. This new substrate allows for an additional screening methodology to identify modulators of the PLCγ family of enzymes.
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    Assessment of folate receptor-β expression in human neoplastic tissues
    (Impact Journals, LLC, 2015-06-10) Shen, Jiayin; Putt, Karson S.; Visscher, Daniel W.; Murphy, Linda; Cohen, Cynthia; Singhal, Sunil; Sandusky, George; Feng, Yang; Dimitrov, Dimiter S.; Low, Philip S.; Department of Pathology & Laboratory Medicine, IU School of Medicine
    Over-expression of folate receptor alpha on cancer cells has been frequently exploited for delivery of folate-targeted imaging and therapeutic agents to tumors. Because limited information exists on expression of the beta isoform of the folate receptor in human cancers (FR-β), we have evaluated the immunohistochemical staining pattern of FR-β in 992 tumor sections from 20 different human cancer types using a new anti-human FR-β monoclonal antibody. FR-β expression was shown to be more pronounced in cells within the stroma, primarily macrophages and macrophage-like cells than cancer cells in every cancer type studied. Moreover, FR-β expression in both cancer and stromal cells was found to be statistically more prominent in females than males. A significant positive correlation was also observed between FR-β expression on stromal cells and both the stage of the cancer and the presence of lymph node metastases. Based on these data we conclude FR-β may constitute a good target for specific delivery of therapeutic agents to activated macrophages and that accumulation of FR-β positive macrophages in the stroma could serve as a useful indicator of a tumor's metastatic potential.