Journal: bioRxiv
Article Title: ASPARAGINE-RICH METASTATIC NICHES DRIVE PROSTATE CANCER ORGANOTROPISM BY ENABLING TRANSLATIONAL REWIRING TOWARD N-GLYCOSYLATED PROTEINS
doi: 10.64898/2026.02.27.708521
Figure Lengend Snippet: (A) Western blot analysis of ASNS in metastatic cells isolated from bone (B-M-1, B-M-2) and lung (L-M-1, L-M-2) lesions. Vinculin was used as loading control. The image is representative of three independent experiments. (B) Schematic representation of asparaginyl-tRNA synthetase 1 (NARS1) mechanism of action. (C) NARS1 mRNA levels in PC3 cells following NARS1 silencing. Cells were transfected with NARS1-targeting small interfering RNA (siRNA) or negative control, and mRNA levels were evaluated after 5 days of incubation in 3D cultures (3D-C) by quantitative RT-PCR, using scramble-transfected cells as reference. (D) Relative cell number of PC3 cells silenced for NARS1 and cultured under standard 2D conditions for 5 days in the presence or absence of Asn (0.1 mM). One-way ANOVA with Sidak’s correction. (E-G) Number of putative N-glycosylation sites in proteins encoded by genes up- or down-regulated in metastatic cells derived from bone (E), lung (F), and liver (G) relative to primary tumor (PT). RNA-seq analysis was conducted as described in . Values are expressed relative to total protein number. (H-I) Fractional enrichment of UDP-GlcNAc isotopologues. PC3 cells were grown in 2D or 3D-C for 5 days and subsequently incubated in a medium containing U- 13 C-glucose for 24h. Labeling enrichment was evaluated by LC-MS analysis, and isotopologue abundance is reported as relative to total UDP-GlcNAc amount. Welch’s t test. (J) Labeling (m+5) enrichment of penotose phosphates from U- 13 C-glucose in PC3 cells growing in 2D or 3D-C for 5 days and subsequently incubated in a medium containing U- 13 C-glucose for 24h. Labeling enrichment was evaluated by LC-MS analysis. (K, L, P) Western blot analysis of GFPT1 (K), STT3a (L), and CD44 (P) expression in PC3 cells silenced for GFPT1, STT3a/b, and CD44 respectively after 48h of gene silencing. Vinculin was used as a loading control. The image is representative of three independent experiments. (M) Concanavalin A lectin binding assay performed on lysates from PC3 cells silenced or not for GFPT1 or STT3a/b and cultured in 3D-C for 5 days. Immunoblot for vinculin was used to confirm equal protein loading across samples. The image is representative of three independent experiments. (N-O) Adhesion of PC3 3D-C to collagen type I (L) and hyaluronic acid (M). Cells were cultured with Asn (0,1 mM) for 5 days and allowed to adhere for 15 min to plates coated with matrix components as reported. Adherent cells were quantified and data are shown relative to untreated cells. Welch’s t-test.
Article Snippet: Membranes were incubated for 1h at room temperature in blocking buffer (5% non-fat dry milk (SantaCruz Biotechnology #sc-2325) in PBS-Tween 0.1%), and then incubated at 4°C over-night with primary antibodies against either ATF-4 (Cell Signaling Technology #11815), ASNS (Cell Signaling Technology #92479S), Phospho-mTOR (Ser2448) (Cell Signaling Technology #5536S), mTOR (Cell Signaling Technology #2983), Phospho-S6K1(Thr389) (Cell Signalig Technology #9205), S6K1 (Cell Signaling Technology #9202), CD44 (Cell Signaling Technology #3570), GFPT1 (ABClonal #A20873), STT3a (Santa Cruz Biotechology #sc-390227), Vinculin (Santa Cruz Biotechology #sc-59803), β-Actin (Santa Cruz Biotechology #sc-47778).
Techniques: Western Blot, Isolation, Control, Transfection, Small Interfering RNA, Negative Control, Incubation, Quantitative RT-PCR, Cell Culture, Glycoproteomics, Derivative Assay, RNA Sequencing, Labeling, Liquid Chromatography with Mass Spectroscopy, Expressing, Binding Assay