Biology subjects

Anzai, T.

Publications and source records attributed to Anzai, T..

4 recordsLinked to original sources

bioRxiv2021

Identification of CD73 as the antigen of an antigen-unknown monoclonal antibody established by exosome immunization, and its antibody-drug conjugate exerts an antitumor effect on glioblastoma cell lines

Development of antibodies against the native structure of membrane proteins with multiple transmembrane domains is challenging because it is difficult to prepare antigens with native structures. Previously, we successfully developed a monoclonal antibody against multi-pass membrane protein TMEM180 by exosome immunization in rats. This approach yielded antibod-ies that recognized cancer-specific antigens on the exosome. In this study, we performed im-munoprecipitation using magnetic beads to identify the antigen of one of the rat antibody clones, 0614, as CD73. We then converted antibody 0614 to human chimeric antibody 0614-5 and found that the humanized antibody did not inhibit CD73 enzymatic activity. Glioblastoma (GB) was the cancer type with the highest expression of CD73 in the tumor relative to healthy tissue. An antibody-drug conjugate (ADC) of 0614-5 exerted an antitumor effect on GB cell lines according to expression of CD73. The 0614-5-ADC could be used to treat cancers with high CD73 expression. In addition, our strategy could be used to determine the antigen of any antibody produced by exosome immunization.

biophysics↗

bioRxiv2020

TMEM180 contributes to colorectal cancer proliferation through intracellular metabolic pathways

TMEM180, a novel colon cancer-specific membrane protein with a 12-transmembrane topology, is upregulated at low oxygen. Previously, we established a humanized monoclonal antibody against TMEM180 aimed at clinical trials. Prior to such trials, it is necessary to clarify the function of this molecule in cancer. To compare SW480 human colon cancer cells and their TMEM180-knockdown derivatives, we analyzed proliferation and oxygen consumption, and also performed phosphorylation proteomics, metabolomics, and next-generation sequencing. The results revealed that TMEM180 promoted the growth of colon cancer but had almost no effect on oxygen consumption or expression of phosphorylated proteins. By contrast, glycolysis differed dramatically between SW480 and TMEM180-knockdown cells. TMEM180 promotes nitric oxide synthesis, suggesting that it promotes glucose metabolism and glutamine metabolism, thereby contributing to cancer growth. Overall, the results of this study support the clinical development of an anti-TMEM180 antibody.

cancer biology↗

bioRxiv2019

Topological analysis of TMEM180, a newly identified membrane protein that is highly expressed in colorectal cancer cells

New target molecules for diagnosis of and drug development for colorectal cancer (CRC) are always in great demand. Previously, we identified a new colorectal cancer-specific protein, TMEM180, and successfully developed an anti-TMEM180 monoclonal antibody (mAb) for the diagnosis and treatment of CRC. Although TMEM180 is categorized as a member of the cation symporter family and multi-pass membrane protein, little is known about its function. In this study, we examined topology of this membrane protein and analyzed its function. Using a homology model of human TMEM180, we experimentally determined that the protein has 12 transmembrane domains, and that its N-terminal and C-termini are exposed extracellularly. Moreover, we found that the putative cation-binding site of TMEM180 is conserved among orthologs, and that its position is similar to that of melibiose transporter MelB. These results suggest that TMEM180 acts as a cation symporter. Our topological analysis based on the homology model provides insight into functional and structural roles of TMEM180 that may help to elucidate the pathology of CRC.\n\nHighlightsO_LIA homology model of human TMEM180 was generated by secondary structure prediction.\nC_LIO_LIPutative cation-binding residues are conserved in TMEM180 orthologs.\nC_LIO_LIBoth the N-terminus and C-terminus of TMEM180 are extracellularly exposed.\nC_LIO_LITMEM180 is a 12-transmembrane protein.\nC_LIO_LITMEM180 could act as a cation symporter.\nC_LI

biophysics↗

bioRxiv2018

Significant antitumour effect of an antibody against TMEM180, a new cancer-specific molecule

The present state of therapy for colorectal cancer (CRC) is far from satisfactory, highlighting the need for new targets for this disease. We identified a new colorectal cancer (CRC)-specific molecule, TMEM180, a predicted eleven-pass transmembrane protein that apparently functions as a cation symporter. Our anti-TMEM180 monoclonal antibody (mAb) eradicated SW480 CRC xenografts in mice. The TMEM180 promoter region contains ten hypoxia-responsive element consensus sequences; accordingly SW480 cells upregulated TMEM180 under low-oxygen conditions. TMEM180 expression in SW480 cells was positively correlated with anchorage-independent colony formation and tumourigenesis. TMEM180-positive SW480 cells resided at the tumour-stroma interface manifested by SMA-positive fibroblasts, also known as the tumour niche. Some clusters of TMEM180-positive cells adjacent to the niche were integrin 6-positive. These data indicate that TMEM180 represents a possible cancer stem cell marker and that a mAb against this protein could be used as antibody-based therapeutic against CRC.

cancer biology↗