A novel approach for on line monitoring of apoptotic cell shrinkage in individual live lymphocytes

Intracellular esterase activity in living cells may distinguish between metastatic and tumor-free lymph nodes

“…However, after the LN cell exposure to autologous tumor tissue, the cell size did not exhibit changes in cells derived from tumor-involved LNs, while in tumor-free lymph nodes, a cell size increase was observed (Table 4). Even though the previous studies demonstrated a correlation between cell radii and FDA hydrolysis rates [20], in the present work the Pearson correlation coefficient for the FDA hydrolysis rate and cell area did not exceed 20% in any experimental group. These results may indicate that the size of lymph node cells, even though partly contributing to changes in FDA hydrolysis rate, is not the major parameter that can account for the significant differences between cells from metastatic and non-metastatic lymph nodes.…”

“…Here we report a new functional assay for the evaluation of lymph node involvement in metastasis that may be performed before the traditional procedure of lymph node histological examination. The FDA staining, occurring only in living cells and applicable in their kinetic studies, is known to indicate a specific cell status such as activation [17,18] or apoptosis [19,20], and to indirectly demonstrate the general nonspecific mechanisms involved in cancer development [16,23].…”

“…Our previous studies have shown an association between cell size and cellular rate of FDA hydrolysis in peripheral blood leukocytes [20]. In the present work, we evaluated the size of LN cells by cell image area.…”

“…Early activation events following cell incubation with and without either phytohemagglutinin or autologous tumor tissue, as measured by FDA staining, reflect differences in intracellular conditions related to the enzymatic activity, cell size, cell surface status and cytoplasmic membrane permeability, as well as cell type, cell cycle stage, etc. [17][18][19][20][21][22]. Moreover, recently, we have shown that, in BC patients, the enzymatic activity of peripheral blood cells interacting with autologous tumor antigens, differ remarkably from the enzymatic reactions in healthy individuals.…”

A New Strategy for Fluorogenic Esterase Probes Displaying Low Levels of Non‐specific Hydrolysis

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An ew design for fluorescence probeso fe sterase activity that features ac arboxylate-side pro-fluorophore is demonstrated with boron dipyrromethene (BODIPY)-based probes 1a and 1b.B ecause the design relies on the enzyme-catalyzed hydrolysis of an ester group that is not electronically activated, these probes exhibit as tability to background hydrolysis that is far superior to classical alcohol-side profluorophore-based probes, large signal-to-noise ratios,reduced sensitivity to pH variations, and high enzymatic reactivity.T he utility of probe 1a was established with ar eal-time fluorescencei maging experiment of endogenouse sterase activity that does not require washing of the extracellularmedium.Small molecule-based fluorescent probes of esterase activity provide ap owerful tool for monitoring and imaging aw idev ariety of biological targets. [1] Cell-permeable esterase substrates are often used as proxy for cell viability and cytotoxicity assays, [2] for monitoring in real-time apoptotic processes occurring in blood cells, [3] and for differentiating between metastatic and tumor-free lymph nodes. [4] Furthermore, since esterase activity is involved in the metabolism of many drugs and prodrugs, fluorogenic esterase probesa re useful tools for evaluating the efficacy of various therapeutic ester-bearing drugs by high-throughput screening.

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