Physiological Hypoxia (Physioxia) Impairs the Early Adhesion of Single Lymphoma Cell to Marrow Stromal Cell and Extracellular Matrix. Optical Tweezers Study

Abstract

Adhesion is critical for the maintenance of cellular structures as well as intercellular communication, and its dysfunction occurs prevalently during cancer progression. Recently, a growing number of studies indicated the ability of oxygen to regulate adhesion molecules expression, however, the influence of physiological hypoxia (physioxia) on cell adhesion remains elusive. Thus, here we aimed: (i) to develop an optical tweezers based assay to precisely evaluate single diffuse large B-cell lymphoma (DLBCL) cell adhesion to neighbor cells (mesenchymal stromal cells) and extracellular matrix (Matrigel) under normoxia and physioxia; and, (ii) to explore the role of integrins in adhesion of single lymphoma cell. We identified the pronouncedly reduced adhesive properties of lymphoma cell lines and primary lymphocytes B under physioxia to both stromal cells and Matrigel. Corresponding effects were shown in bulk adhesion assays. Then we emphasized that impaired β1, β2 integrins, and cadherin-2 expression, studied by confocal microscopy, account for reduction in lymphocyte adhesion in physioxia. Additionally, the blockade studies conducted with anti-integrin antibodies have revealed the critical role of integrins in lymphoma adhesion. To summarize, the presented approach allows for precise confirmation of the changes in single cell adhesion properties provoked by physiological hypoxia. Thus, our findings reveal an unprecedented role of using physiologically relevant oxygen conditioning and single cell adhesion approaches when investigating tumor adhesion in vitro.

Identifying Candidate Genes for Hypoxia Adaptation of Tibet Chicken Embryos by Selection Signature Analyses and RNA Sequencing

“…From Figure 5 , we can see that many terms were obviously enriched relating to sodium ion and amino acid transport (such as GO:0006814 ~ sodium ion transport; GO:0015190 ~ L-leucine transmembrane transporter activity; GO:0015191 ~ L-methionine transmembrane transporter activity; GO:0015808 ~ L-alanine transport; GO:0015810 ~ aspartate transport) and gene expression regulation (such as GO:0003682 ~ chromatin binding; GO:0045892 ~ negative regulation of transcription, DNA-templated; GO:0044822 ~ poly(A) RNA binding; GO:0000166 ~ nucleotide binding; GO:0007266 ~ Rho protein signal transduction; GO:0022627 ~ cytosolic small ribosomal subunit; GO:0005096 ~ GTPase activator activity; GO:0001047 ~ core promoter binding), cell adhesion (GO:0007155 ~ cell adhesion; gga04520: adherens junction; gga04514: cell adhesion molecules (CAMs)) and angiogenesis (GO:0001525 ~ angiogenesis), etc. These results were consistent with previous studies of different animal hearts in hypoxia [ 9 , 50 , 53 , 54 , 55 , 56 ]. Regulating angiogenesis may be one of the important approaches for animals to adapt to hypoxia [ 9 , 50 , 53 ].…”

“…Adhesion is vital for the cellular structure maintenance. Hypoxia could impair the early adhesion of single lymphoma cells [ 55 ], which implies the role of cell adhesion in animal hypoxia adaptation. The results suggested that biological functions such as sodium ion and amino acid transports, gene expression regulation, cell adhesion and angiogenesis may play important roles in maintaining the normal function and development of chicken embryonic hearts under hypoxic conditions.…”

RNA-seq reveals tight junction-relevant erythropoietic fate induced by OCT4 in human hair follicle mesenchymal stem cells

“…Cell-extracellular matrix adhesion was assayed as previously reported with minor modi cations (28,29). 2×10 5 cells per well were seeded onto Matrigel-coated 24-well plates and incubated for 6 hours until hHFMSCs adhered to the plates and stable connection was formed.…”

Differentiation of single lymphoma primary cells and normal B-cells based on their adhesion to mesenchymal stromal cells in optical tweezers

“…In addition, the manipulation process should ideally also not damage the cells, but still enable maintaining the cell-cell contact, thus, permitting a controlled observation of how the interaction process unfolds. Meanwhile, when the adhesion between two living cells was formed, any of cell could not be picked up without cell membrane rupture during the detachment process, as was evidenced in previous works 21,49,52 .…”

“…The optical tweezers were previously used by our group in a variety of applications, e.g cell-to-cell adhesion 52,60 , localized hyperthermia 61 , and drug testing 62 . The configuration was adapted to trap and move individual B-cells.…”