ASCT2 regulates glutamine uptake and cell growth in endometrial carcinoma

Abstract

Glutamine commonly becomes a conditionally essential amino acid in cancer. Glutamine is supplied to the cell by transporters such as ASCT2 (SLC1A5), which is frequently upregulated in multiple cancers. Here we investigated the expression of ASCT2 in endometrial carcinoma, and evaluated the contribution of ASCT2 to glutamine uptake and endometrial cancer cell growth. Analysis of human gene expression data showed that ASCT2 was significantly upregulated in both endometrioid and serous subtypes of endometrial carcinoma, compared to normal, age-matched endometrium. Furthermore, immunohistochemical staining of primary human endometrioid adenocarcinomas showed that tumours stain positive for ASCT2 in either a uniform or mosaic expression pattern, while normal adjacent glands appeared predominantly negative for ASCT2 staining. Chemical inhibition of glutamine transport by benzylserine or GPNA led to a significant decrease in endometrial cancer cell growth and spheroid cross-sectional area. ASCT2 knockdown recapitulated the decrease of cell growth and spheroid cross-sectional area in HEC1A cells, suggesting a reliance on ASCT2-mediated glutamine uptake. ASCT2 knockdown in Ishikawa cells led to lower glutamine uptake and cell growth, but did not affect spheroid area. Ishikawa cells express higher levels of the glutamine transporter SNAT1 compared to HEC1A cells, suggesting these cells may rely on both ASCT2 and SNAT1 for glutamine uptake. Since SNAT1 is also significantly upregulated in the endometrioid and serous subtypes, these data indicate that ASCT2 and SNAT1 could be used as markers of malignancy, and/or potential therapeutic targets in patients with endometrial carcinoma.

Methylation‑associated silencing of miR‑638 promotes endometrial carcinoma progression by targeting MEF2C

“…A pooled analysis of individual-level data from 10 cohort and 14 case-control studies identified that patients with these 2 endometrial cancer types shared a number of common etiologic factors, including parity, oral contraceptive use, cigarette smoking, age at menarche and presence of diabetes (24). Furthermore, shared molecular regulatory mechanisms among these 2 pathological subtypes of Ec have been previously reported, such as solute carrier family 1 member 5 regulating glutamine uptake and cell growth in Ec (25). In the present study, the differences in methylation status and expression levels of miR-638, as well as expression levels of MEF2C, were compared among cancerous tissues and non-cancerous tissues in clinical samples from patients with endometrioid adenocarcinoma and serous carcinoma.…”

Stromal epigenetic alterations drive metabolic and neuroendocrine prostate cancer reprogramming

“…However, glutamine, a conditionally essential amino acid that is the most commonly depleted amino acid in solid tumors, can serve as a carbon source for the TCA cycle and as a nitrogen source for nucleotide biosynthesis (44). Like glucose, amino acids cannot cross the lipid bilayer without transporter proteins, and amino acid transporter expression is positively correlated with growth and cancer (45). We found the expression levels of glutamine transporters and glutaminase in CWR22RV1 and C4-2B cells are potentiated by glu-aggressive differentiation state.…”

Sorting nexin 27 (SNX27) regulates the trafficking and activity of the glutamine transporter ASCT2

“…Briefly, 10 6 HeLa cells in PBS were fixed in 70% ethanol for at least 2 hrs on ice. After fixation step, cells were pelleted and washed with PBS before suspending cells with staining solution containing 20 µg/ml of PI, 0.1% of Triton X-100 and 0.2 mg/ml of DNase-free RNase A in PBS for 15 min at 37 degree.…”

“…There have been significant efforts to pharmacologically target ASCT2 for the inhibition of cancer cell growth. For example, monoclonal antibodies against ASCT2 or chemical ASCT2 inhibitors, such as benzylserine and gammal-Glutamyl-p-nitroanilide (GPNA), have been shown to inhibit cell growth of various cancers (5)(6)(7). While the impact of cell proliferation through ASCT2 activity is clear, the molecular details of how ASCT2 activity is regulated are poorly understood.…”