Positive flow-spines and contact 3-manifolds

We say that a contact structure on a closed, connected, oriented, smooth 3-manifold is supported by a flow-spine if it has a contact form whose Reeb flow is a flow of the flow-spine. We then define a map from the set of positive flow-spines to the set of contact 3-manifolds up to contactomorphism by sending a positive flow-spine to the supported contact 3-manifold and show that this map is well-defined and surjective. We also determine the contact 3-manifolds supported by positive flow-spines with up to 3 vertices. As an application, we introduce the complexity for contact 3-manifolds and determine the contact 3-manifolds with complexity up to 3.Comment: 73 pages, 78 figures. The last subsection was remove

Positive flow-spines and contact 3-manifolds, II

This paper corresponds to Section 8 of arXiv:1912.05774v3 [math.GT]. The contents until Section 7 are published in Annali di Matematica Pura ed Applicata as a separate paper. In that paper, it is proved that for any positive flow-spine P of a closed, oriented 3-manifold M, there exists a unique contact structure supported by P up to isotopy. In particular, this defines a map from the set of isotopy classes of positive flow-spines of M to the set of isotopy classes of contact structures on M. In this paper, we show that this map is surjective. As a corollary, we show that any flow-spine can be deformed to a positive flow-spine by applying first and second regular moves successively.Comment: 17 pages and 22 figures. This paper covers Section 8 of the preprint arXiv:1912.05774v3 [math.GT]. The part until Section 7 is covered in arXiv:1912.05774v4 [math.GT] as a separate pape

A Novel Artificially Humanized Anti-Cripto-1 Antibody Suppressing Cancer Cell Growth

Cripto-1 is a member of the EGF-CFC/FRL1/Cryptic family and is involved in embryonic development and carcinogenesis. We designed a novel anti-Cripto-1 artificial antibody and assessed the recognition to the antigen and the potential to suppress the growth of cancer stem cells. First, single chain antibody clones were isolated by bio-panning with the affinity to recombinant Cripto-1 protein from our original phage-display library. Then, the variable regions of heavy chain VH and light chain VL in each clone were fused to constant regions of heavy chain CH and light chain CL regions respectively. These fused genes were expressed in ExpiCHO-S cells to produce artificial humanized antibodies against Cripto-1. After evaluation of the expression levels, one clone was selected and the anti-Cripto-1 antibody was produced and purified. The purified antibody showed affinity to recombinant Cripto-1 at 1.1 pmol and immunoreactivity to cancer tissues and cell lines. The antibody was available to detect the immunoreactivity in tissue microarrays of malignant tumors as well as in Cripto-1 overexpressing cells. Simultaneously, the antibody exhibited the potential to suppress the growth of human colon cancer derived GEO cells overexpressing Cripto-1 with IC50 at approximately 110 nM. The artificially humanized antibody is proposed to be a good candidate to target cancer cells overexpressing Cripto-1

Cripto-1 as a Potential Target of Cancer Stem Cells for Immunotherapy

Simple Summary Cancer immunotherapy is gaining attention as a potential fourth treatment following surgery, chemotherapy, and radiation therapy. Cancer stem cells have recently been recognized and validated as a key target for cancer treatment. Cripto-1, which is a GPI-anchored membrane-bound protein that functions as a co-receptor of Nodal, is a marker of cancer stem cells. Since Nodal is a member of the TGF-beta family, which performs an important role in stem cells and cancer stem cells, the inhibition of Cripto-1 could be a strategy by which to block Nodal signaling and thereby suppress cancer stem cells. We propose that Cripto-1 may be a novel target for cancer immunotherapy. The immune system has been found to be suppressed in cancer patients. Cancer cells are extremely resistant to chemotherapeutic drugs, conventional immunotherapy, or cancer antigen vaccine therapy. Cancer immunotherapy, which is mainly based on immune checkpoint inhibitors, such as those for PD-1, PD-L1, and CTLA4, is an effective treatment method. However, no immunotherapeutic target has been found that retains validity in the face of tumor diversity. The transforming growth factor (TGF)-beta cytokine family possesses broad biological activity and is involved in the induction and/or transdifferentiation of helper T cells, which are important in immunotherapy. Nodal is a member of the TGF-beta family playing important roles in tissue stem cells and cancer stem cells (CSCs), interacting with the co-receptor Cripto-1, as well as with Activin type IB (Alk4) and Activin typeIIreceptors, and maintaining stemness and Notch and Wnt/beta-catenin signaling in CSCs. In recent years, it has been reported that Cripto-1 could be a potential therapeutic target in CSCs. Here, we review the accumulated literature on the molecular mechanisms by which Cripto-1 functions in CSCs and discuss the potential of Cripto-1 as an immunotherapeutic target in CSCs

Eosinophil Cationic Protein Shows Survival Effect on H9c2 Cardiac Myoblast Cells with Enhanced Phosphorylation of ERK and Akt/GSK-3β under Oxidative Stress

Eosinophil cationic protein (ECP) is well known as a cationic protein contained in the basic granules of activated eosinophils. Recent studies have reported that ECP exhibits novel activities on various types of cells, including rat neonatal cardiomyocytes. Here we evaluated the effects of ECP on rat cardiac myoblast H9c2 cells. Our results showed that ECP enhanced the survival of the cells, in part by promoting the ERK and Akt/GSK-3β signaling pathways. ECP attenuated the cytotoxic effects of H2O2 on H9c2 cells as well as the production of reactive oxygen species, the number of apoptotic cells and caspase 3/7 activity in the cells. In conclusion, ECP activated the ERK and Akt/GSK-3β pathways, resulting in anti-oxidative effects on H9c2 cells that attenuated apoptosis

Isolation and characterization of cancer stem cells derived from human glioblastoma

Cancer stem cell (CSC) is considered as a cause of cancer recurrence and metastasis. Simultaneously CSCs are responsible for the heterogeneous population in tumor tissues due to their differentiation potential. However, the characterizations of CSCs are still not enough and cancer stem cell lines widely available is desired to be established for the advancement of cancer research. In this study, we tried to isolate and characterize stem like cells from human glioblastoma cell line U-251MG cells. U-251MG P1 cells, which was previously condensed in the presence of hyaluronic acid as CD44 positive population were subjected to single cell isolation procedure. Although 5 clones were isolated, only one clone exhibited high expression of CD44, Nanog, OCT3/4 and SOX2, and named U-251MGSC1. The sphere forming ability of U-251MGSC1 cell was significantly higher than the parental U-251MG cells. Tumorigenicity of U-251MG-SC1 cells were higher than that of U-251MG cells. U-251MGSC1 cells exhibited higher expression of CD44, SOX2, Nestin and A2B5 than U-251MG cells in vitro and in vivo. The expression of GFAP and NF-M was enhanced when the cells were treated with the conditioned medium of U-251MG cells indicating the potential of differentiation. Sphere forming ability was more efficient than that of U-251MG cells and was enhanced in the presence of hyaluronic acid, which enhanced the cell growth as well. U-251MGSC1 cells exhibited rapid growth tumor in nude mice and efficient metastatic ability in transmembrane assay when compared with U-251MG cells. As the result, we concluded U-251MGSC1 cell was a glioblastoma CSC line derived from the parental U-251MG cells. U-251MGSC1 cells will be a good tool to develop effective therapeutic agents against CSCs and to elucidate the properties of glioma derived CSCs and the mechanism of tumor development in brain

Cancer Stem Cell Microenvironment Models with Biomaterial Scaffolds In Vitro

Defined by its potential for self-renewal, differentiation and tumorigenicity, cancer stem cells (CSCs) are considered responsible for drug resistance and relapse. To understand the behavior of CSC, the effects of the microenvironment in each tissue are a matter of great concerns for scientists in cancer biology. However, there are many complicated obstacles in the mimicking the microenvironment of CSCs even with current advanced technology. In this context, novel biomaterials have widely been assessed as in vitro platforms for their ability to mimic cancer microenvironment. These efforts should be successful to identify and characterize various CSCs specific in each type of cancer. Therefore, extracellular matrix scaffolds made of biomaterial will modulate the interactions and facilitate the investigation of CSC associated with biological phenomena simplifying the complexity of the microenvironment. In this review, we summarize latest advances in biomaterial scaffolds, which are exploited to mimic CSC microenvironment, and their chemical and biological requirements with discussion. The discussion includes the possible effects on both cells in tumors and microenvironment to propose what the critical factors are in controlling the CSC microenvironment focusing the future investigation. Our insights on their availability in drug screening will also follow the discussion

Stabilization of Pseudomonas aeruginosa Cytochrome c551 by Systematic Amino Acid Substitutions Based on the Structure of Thermophilic Hydrogenobacter thermophilus Cytochrome c552

A heterologous overexpression system for mesophilic Pseudomonas aeruginosa holocytochrome c551 (PA c551) was established using Escherichia coli as a host organism. Amino acid residues were systematically substituted in three regions of PA c551 with the corresponding residues from thermophilic Hydrogenobacter thermophilus cytochrome c552 (HT c552), which has similar main chain folding to PA c551, but is more stable to heat. Thermodynamic properties of PA c551 with one of three single mutations (Phe-7 to Ala, Phe-34 to Tyr, or Val-78 to Ile) showed that these mutants had increased thermostability compared with that of the wild-type. Ala-7 and Ile-78 may contribute to the thermostability by tighter hydrophobic packing, which is indicated by the three dimensional structure comparison of PA c551 with HT c552. In the Phe-34 to Tyr mutant, the hydroxyl group of the Tyr residue and the guanidyl base of Arg-47 formed a hydrogen bond, which did not exist between the corresponding residues in HT c552. We also found that stability of mutant proteins to denaturation by guanidine hydrochloride correlated with that against the thermal denaturation. These results and others described here suggest that significant stabilization of PA c551 can be achieved through a few amino acid substitutions determined by molecular modeling with reference to the structure of HT c552. The higher stability of HT c552 may in part be attributed to some of these substitutions.This work was supported in part by grants from the Japanese Ministry of Education, Science and Culture