CELLULAR IMAGING LABORATORY

At the Cellular Imaging Laboratory, we are strongly committed to the development and application of modern optical imaging methods that will enable us and others to understand the complex organization within and between cells. Our lab’s special interest is the functional analysis of cell division related proteins using both human cancer cells and tumor-like callus tissues of plants. In human cancer cells we analyze the role of SUMO (small ubiquitin related modifier) proteins. We are especially interested in their role during cancer development and metastasis. Our lab also takes part in various scientific collaboration projects with different research labs.

Our modern imaging center is equipped with a state-of-the-art Confocal Laser Scanning Microscope, a Fluorescence Stereo Microscope, a Real-time Imaging Workstation and powerful image analysis computers with imaging software. With these modern microscopes we can perform protein localization and mobility analyses, three dimensional, time course dynamic analyses of live cells, tissues and organisms. Thanks to the new imaging techniques and the development of new fluorescent dyes and proteins, today’s biological and medical research has increasingly become dependent on microscopy and image analysis. It is now possible to specifically label virtually any molecule and directly probe its function in live cells by light microscopy.

This ability to visualize the dynamics of proteins in vesicles, organelles, cells and tissue has begun to provide new insights into how cells function in health and disease. Such work yields unique mechanistic insight by directly illustrating the complex spatial-temporal dynamics of fundamental cellular processes such as mitosis, morphogenesis, polarization, embryonic development, membrane trafficking and cytoskeleton dynamics. Many of these processes are highly dynamic and are challenging to image by traditional means. In this aim, we are strongly committed to the development and application of optical imaging methods that will enable us and others to understand the complex organization within and between cells.

Microscopy and cytometry application of a new cell proliferation assay

Labeling, detection and quantification of cells in the S-phase (DNA synthesis) of cell cycle progression are crucial in characterizing the cellular responses to various treatments and genetic modifications. Bromo-deoxyuridine (BrdU) labeling of cells followed by antibody staining is the standard method for detecting cells in the S-phase. Antibody detection of BrdU involves harsh treatments or nuclease digestion to facilitate epitope access. Moreover in plants cells, cell wall digestion is also necessary. These steps could interfere with cellular morphology and are time-consuming. We have optimized the recently developed ethynyl-deoxyuridine (EdU) method on plant cell cultures and seed-derived roots as well as on isolated plant nuclei using confocal laser scanning microscopy and flow cytometry.

SUMO and Human Cancer Therapy

Small ubiquitin-related modifiers (SUMO) are post-translational protein modifiers that are ligated to target proteins in a manner similar to ubiquitin. Post-translational modifications play a cardinal role in carcinogenesis affecting important regulatory proteins, such as transcriptional factors, growth factors or oncoproteins. SUMO conjugation (sumoylation) also impacts many cellular pathways through modulation of transcriptional activity, protein stability and protein subcellular localization. SUMO conjugation is necessary for cell division and several substrates of sumoylation are major players in oncogenesis, tumor suppression and cancer metastasis. Thus, it is conceivable to suggest that alterations of the sumoylation network ultimately affect cancer-related molecular pathways.

Therefore the discovery of novel sumoylation-modulatory molecules could yield potential medical applications such as cancer treatment. In collaboration with the Laboratory of Functional Genomics, BRC, Szeged, we aim to exploit this possibility to discover new synthetic molecules that change the course of carcinogenesis by modifying the SUMO pathway. To achieve this goal, we are screening diverse small molecule libraries to discover novel compounds that interfere with the localization and conjugation patterns of human SUMO proteins using high-throughput live-cell confocal laser scanning microscopy. We have already identified many novel chemicals that affect SUMO-1 localization, cell viability, morphology and cell division. We have also discovered new non-toxic autofluorescent chemicals that can be used as live cell organelle probes.