Oncogenic transformation of NIH/3T3 cells by the overexpression of L-type amino acid transporter 1, a promising anti-cancer target

Abstract

L-type amino acid transporter 1 (LAT1)/SLC7A5 is the first identified CD98 light chain disulfide linked to the CD98 heavy chain (CD98hc/SLC3A2). LAT1 transports large neutral amino acids, including leucine, which activates mTOR, and is highly expressed in human cancers. We investigated the oncogenicity of human LAT1 introduced to NIH/3T3 cells by retrovirus infection. NIH/3T3 cell lines stably expressing human native (164C) or mutant (164S) LAT1 (naLAT1/3T3 or muLAT1/3T3, respectively) were established. We confirmed that endogenous mouse CD98hc forms a disulfide bond with exogenous human LAT1 in naLAT1/3T3, but not in muLAT1/3T3. Endogenous mouse CD98hc mRNA increased in both naNIH/3T3 and muLAT1/3T3, and a similar amount of exogenous human LAT1 protein was detected in both cell lines. Furthermore, naLAT1/3T3 and muLAT1/3T3 cell lines were evaluated for cell growth-related phenotypes (phosphorylation of ERK, cell-cycle progression) and cell malignancy-related phenotypes (anchorage-independent cell growth, tumor formation in nude mice). naLAT1/3T3 had stronger growth-and malignancy-related phenotypes than NIH/3T3 and muLAT1/3T3, suggesting the oncogenicity of native LAT1 through its interaction with CD98hc. Anti-LAT1 monoclonal antibodies significantly inhibited in vitro cell proliferation and in vivo tumor growth of naLAT1/3T3 cells in nude mice, demonstrating LAT1 to be a promising anti-cancer target. Oncotarget 12 www.oncotarget.complotted against the ΔMFI, and the dissociation constant: K D (nmol/L) and avidity constant: K A (M -1 ) were determined from the slope of linear regression. Statistical analysisAll data are shown as the average ± SEM. The criteria for significance were * P < 0.05, ** P < 0.01, and *** P < 0.001. The data were analyzed by one-or two-way analysis of variance (ANOVA) followed by Tukey's post hoc multiple comparison test (Figures 1-5).

Zwitterionic Amino Acid-Derived Polyacrylates as Smart Materials Exhibiting Cellular Specificity and Therapeutic Activity

“…Out of the investigated polymers, P­( O Bzl-Ser 23 - stat -Glu 67 ) revealed the ideal balance of Bzl and Glu. Although the BzlSer units are lipophilic, cationic building blocks, Glu provides the polymers with low-fouling properties, increased solubility in aqueous media, as well as cellular specificity mediated by transporter interactions, which are reduced in NIH 3T3 due to the absence of specific transporters. , …”

“…Although the BzlSer units are lipophilic, cationic building blocks, Glu provides the polymers with lowfouling properties, increased solubility in aqueous media, as well as cellular specificity mediated by transporter interactions, which are reduced in NIH 3T3 due to the absence of specific transporters. 58,59 ■ CONCLUSIONS The synthesis of novel, zwitterionic Glu-functionalized polymers by RAFT polymerization was demonstrated. Defined polymers with protected side chains were prepared, Cy5labeled, and deprotected to yield tailored amino acidfunctionalized polymers.…”

Adipocytic Glutamine Synthetase Upregulation via Altered Histone Methylation Promotes 5FU Chemoresistance in Peritoneal Carcinomatosis of Colorectal Cancer

“…Amino acid metabolism has been shown to participate in mTOR signaling ( 32 , 33 ). To detect whether mTOR signaling is involved in adipocyte and GS-induced chemoresistance of CRC to 5FU, we established co-culture models of adipocytes and CRC tumor cells using mouse adipocytes differentiated from 3T3-L1 cells AD co-cultured with mouse tumor cell lines B16, CT26, and MC38, respectively.…”

CD98 regulates the phosphorylation of HER2 and a bispecific anti‐HER2/CD98 antibody inhibits the growth signal of human breast cancer cells

“…CD98, also referred to solute carrier (SLC) 3A2, binds to six CD98lcs of the SLC7A amino acid transporter family (SLC7A5–7A8, 7A10, and 7A11) (Palacín et al, 2005). We produced mAb recognizing L‐type amino acid transporter 1 (LAT1)/SLC7A5 (Ohno et al, 2008; Ueda et al, 2019), and demonstrated the oncogenicity of LAT1 by the targeted disruption of the chicken LAT1 gene in DT40 cells (Ohkawa et al, 2011) and the oncogenic transformation of NIH3T3 cells through the overexpression of human LAT1 (Hayashi et al, 2021). We also produced α‐xCT/SLC7A11 mAb and identified xCT as a protein required for the maintenance of cancer stem cells (Ishimoto et al, 2011; Tsuchihashi et al, 2016; Yae et al, 2012).…”