Journal: Genes to Cells

Article Title: Alternative Splicing of FBLN2 Generates a Prometastatic Extracellular Matrix in Gastrointestinal Cancers by Determining N‐Glycosylation of Fibulin 2

doi: 10.1111/gtc.70027

Figure Lengend Snippet: Variant 2 is the major FBLN2 splice variant expressed in the fibroblasts of gastrointestinal cancers. (A) Schematic representation of the human FBLN2 gene. Exon (E) 9 (magenta) is included or excluded in variant 1 (v1) or variant 2 (v2) mRNAs, respectively. (B) Difference in splicing of FBLN2 exon 9 between normal (N) and primary tumor (T) tissue for 16 types of cancer in the TCGASpliceSeq database. Cancer type abbreviations are as in Table . PSI, percent spliced‐in. The values at the bottom indicate the number of tumor (T) and normal (N) tissues examined. (C, D) Box plots for PSI values of FBLN2 exon 9 determined from RNA‐seq data for normal (N), primary tumor (T), or metastatic liver tumor (M) tissue for four selected cancer types in TCGA (C) or for CRC in GSE50760 (D). (E) RT‐qPCR analysis of the expression of FBLN2 v1 and v2 in normal and primary tumor tissue isolated from CRC patients. Data are means ± SEM ( n = 7 patients). (F) Expression profiles for FBLN2 in CRC tissue determined by scRNA‐seq analysis ( GSE178341 ). The color intensity in the left plot represents the abundance of FBLN2 mRNA as shown by Log (TP10K + 1). TP10K + 1 indicates transcripts per 10 thousand plus one reads. The colors in the right plot correspond to cell identities. ILC, innate lymphoid cell; NK, natural killer. (G) Violin plots for the expression level of FBLN2 in five stromal cell types determined by scRNA‐seq analysis as in (F). (H) Representative immunohistochemical staining of FBLN2 in a tissue section containing normal epithelium isolated from a CRC patient. Boxed regions in the left image are shown at higher magnification in the middle and right images. BV, blood vessel; EL, epithelial layer; LP, lamina propria; MM, muscularis mucosae. Scale bars, 300 μm (left) and 100 μm (middle and right). (I) RT‐qPCR analysis of FBLN2 v1 and v2 expression in primary fibroblasts isolated from normal (N) or primary tumor (T) tissue of gastrointestinal cancer patients. Data are means ± SEM ( n = 6 patients). * p < 0.05, ** p < 0.01, *** p < 0.001, n.s. (not significant) by the Wilcoxon rank sum test followed by Benjamini–Hochberg correction for multiple testing (B, C), by one‐way analysis of variance (ANOVA) followed by Tukey's post hoc test (D), or by the paired t test (E, I).

Article Snippet: This ECM is composed of various fibrous proteins including fibrillar collagens, fibronectin 1 (FN1), and fibulin 2 (FBLN2) (Brassart‐Pasco et al. ; Cox ).

Techniques: Variant Assay, RNA Sequencing, Quantitative RT-PCR, Expressing, Isolation, Immunohistochemical staining, Staining

Journal: Genes to Cells

Article Title: Alternative Splicing of FBLN2 Generates a Prometastatic Extracellular Matrix in Gastrointestinal Cancers by Determining N‐Glycosylation of Fibulin 2

doi: 10.1111/gtc.70027

Figure Lengend Snippet: Splicing of FBLN2 exon 9 determines N‐glycosylation of FBLN2 protein. (A, B) 24N‐T fibroblasts infected (or not) with a recombinant lentivirus encoding FBLN2‐3 × FLAG v1 or v2 were subjected to immunoblot analysis with antibodies to FLAG (A) or to RT‐qPCR analysis of FBLN2 mRNA (B). FN1 expression was analyzed as a loading control in (A). Data in (B) are means ± SEM ( n = 3 independent experiments). (C, D) 24N‐T fibroblasts engineered as in (A) were subjected to immunoprecipitation (IP) with antibodies to FLAG, and the resulting precipitates were subjected to SDS‐PAGE and staining with Oriole fluorescent dye (C) or to immunoblot analysis (IB) of HSPA5 (D). The arrowhead in (C) indicates the position of HSPA5 coprecipitated with FBLN2‐3 × FLAG v2. (E) FBLN2‐3 × FLAG v1 or v2 prepared from culture supernatants of 24N‐T fibroblasts engineered as in (A) was treated (or not) with the indicated glycosidases and then subjected to immunoblot analysis of FLAG. (F) HEK293T cells expressing FBLN2‐3 × FLAG v1 or v2 were treated with various concentrations of tunicamycin, after which medium (culture supernatant) and cell lysate (cells attached to culture dish) were prepared and subjected to immunoblot analysis of FLAG. Oriole staining of the SDS‐PAGE gel and immunoblot analysis of β‐actin were performed as loading controls for medium and cell lysate fractions, respectively. (G) Schematic representation of human FBLN2 v1 and v2 proteins. Triangles indicate the positions of putative N‐glycosylation sites. The positions of cbEGF‐like domains and anaphylatoxin (AT) modules are also shown. (H) Immunoblot analysis of FLAG for HEK293T cells expressing WT or mutant versions of FBLN2‐3 × FLAG v1 or v2 (upper panel). Cell lysates were fractionated by SDS‐PAGE in the presence (ConA gel) or absence (Standard gel) of concanavalin A. Schematic representations of N‐glycosylation sites for v1 (bottom left) and v2 (bottom right) are also shown. (I) FBLN2‐3 × FLAG v1 or v2 immunoprecipitated from 24N‐T fibroblasts engineered as in (A) was subjected to SDS‐PAGE and stained for glycoproteins (upper) or total proteins (lower). The different mobility of protein size markers between glycoprotein gel (upper) and total protein gel (lower) is likely due to the use of distinct molecular weight standards, in which the 180 kDa marker band is glycosylated. (J) Quantification of signal intensity as in (I). Data are means ± SEM ( n = 4 independent experiments). * p < 0.05, *** p < 0.001 by Student's t test (B, J).

Article Snippet: This ECM is composed of various fibrous proteins including fibrillar collagens, fibronectin 1 (FN1), and fibulin 2 (FBLN2) (Brassart‐Pasco et al. ; Cox ).

Techniques: Glycoproteomics, Infection, Recombinant, Western Blot, Quantitative RT-PCR, Expressing, Control, Immunoprecipitation, SDS Page, Staining, Mutagenesis, Molecular Weight, Marker

Journal: Genes to Cells

Article Title: Alternative Splicing of FBLN2 Generates a Prometastatic Extracellular Matrix in Gastrointestinal Cancers by Determining N‐Glycosylation of Fibulin 2

doi: 10.1111/gtc.70027

Figure Lengend Snippet: FBLN2 v2 is less stable and secreted to a lesser extent compared with v1. (A–C) 24N‐T fibroblasts infected with a recombinant retrovirus encoding FBLN2‐3 × FLAG v1 or v2 were subjected to RT‐qPCR analysis of FBLN2 mRNA (A) or to cellular fractionation followed by immunoblot analysis of FLAG (B, C). Quantitative data are means ± SEM ( n = 4 independent experiments). (D–G) 24N‐T fibroblasts engineered as in (A) were incubated with cycloheximide (100 μg/mL) for the indicated times (D) or with various concentrations of MG132 for 6 h (F), after which cell lysates were subjected to immunoblot analysis of FLAG or β‐actin (loading control). Arrowheads indicate the positions of the intracellular forms of FBLN2. Signal intensity for the intracellular forms of v1 and v2 was also determined (E, G), with the data presented as means ± SEM ( n = 4 independent experiments). ** p < 0.01, *** p < 0.001, n.s. by Student's t test (A, C), by repeated measures ANOVA (E), or by two‐way ANOVA (G).

Article Snippet: This ECM is composed of various fibrous proteins including fibrillar collagens, fibronectin 1 (FN1), and fibulin 2 (FBLN2) (Brassart‐Pasco et al. ; Cox ).

Techniques: Infection, Recombinant, Quantitative RT-PCR, Cell Fractionation, Western Blot, Incubation, Control

Journal: Genes to Cells

Article Title: Alternative Splicing of FBLN2 Generates a Prometastatic Extracellular Matrix in Gastrointestinal Cancers by Determining N‐Glycosylation of Fibulin 2

doi: 10.1111/gtc.70027

Figure Lengend Snippet: The ECM environment of CRC tissue exhibits low FBLN2 and high FN1 abundance. (A) Lysates prepared from normal (N) or primary tumor (T) tissue of CRC patients were subjected to immunoblot analysis of FBLN2 with the indicated antibodies. The gel was also stained with Oriole fluorescent dye to allow adjustment for protein loading. (B) Quantification of signal intensity as in (A). Data are means ± SEM ( n = 9 patients). (C) Representative immunohistochemical staining of extracellular FBLN2 (HPA001934) in a section containing primary tumor (T) and adjacent normal (N) tissue isolated from a CRC patient. The boxed regions in the upper image are shown at higher magnification in the lower images. FBLN2 signals in the lamina propria (LP) are indicated by arrowheads in the lower left image. BV, blood vessel; EL, epithelial layer; MM, muscularis mucosae. Scale bars, 1 mm (upper) and 100 μm (lower). (D) Representative immunofluorescence analysis of FBLN2 and FN1 in 21N‐T (upper) or 24N‐T (lower) fibroblasts isolated from rectal cancer or gastric cancer patients, respectively. DNA was stained with 4′,6‐diamidino‐2‐phenylindole (DAPI). Scale bars, 50 μm. (E) Box plots for FN1 mRNA level based on transcripts per million (TPM) in normal (N) and primary tumor (T) tissue for COADREAD in TCGA. (F) Immunoblot analysis of FN1 in lysates prepared from normal (N) and primary tumor (T) tissue of CRC patients. The gel was stained for total proteins with Oriole fluorescent dye. (G) Box plots for FN1 mRNA level based on fragments per kilobase of exon per million mapped reads (FPKM) in normal (N), primary CRC tumor (T), and metastatic liver tumor (M) tissue determined by RNA‐seq analysis ( GSE50760 ) as in Figure . * p < 0.05, ** p < 0.01, *** p < 0.001, n.s. by the paired t test (B), Wilcoxon rank sum test (E) or by one‐way ANOVA followed by Tukey's post hoc test (G).

Article Snippet: This ECM is composed of various fibrous proteins including fibrillar collagens, fibronectin 1 (FN1), and fibulin 2 (FBLN2) (Brassart‐Pasco et al. ; Cox ).

Techniques: Western Blot, Staining, Immunohistochemical staining, Isolation, Immunofluorescence, RNA Sequencing

Journal: Genes to Cells

Article Title: Alternative Splicing of FBLN2 Generates a Prometastatic Extracellular Matrix in Gastrointestinal Cancers by Determining N‐Glycosylation of Fibulin 2

doi: 10.1111/gtc.70027

Figure Lengend Snippet: FBLN2 suppresses the adhesion and migration of CRC cells. (A) Representative results for a transwell migration assay in which HCT 116 cells were seeded on a transwell insert coated (or not) with FN1 (20 μg/mL) or FBLN2 v2 (20 μg/mL) and were then allowed to migrate for 48 h. (B) Quantification of the area of migrated cells as in (A). Data are means ± SEM ( n = 3 independent experiments). (C) Representative results for a transwell migration assay in which HCT 116 cells were seeded on a transwell insert coated (or not) with FN1 (20 μg/mL) and various concentrations of FBLN2 v2 or BSA and were then allowed to migrate for 24 h. (D) Quantification of the area of migrated cells as in (C). Data are means ± SEM ( n = 4 independent experiments). (E) Representative results for a cell adhesion assay in which HCT 116 cells were seeded in low‐attachment dishes coated (or not) with FN1 (2 μg/mL) and various concentrations of FBLN2 v2 or BSA. (F) Quantification of attached cells as in (E). (G) Model for the role of alternative splicing of FBLN2 exon 9 in the remodeling of ECM. Data are means ± SEM ( n = 3 independent experiments). * p < 0.05, ** p < 0.01, *** p < 0.001, n.s. by one‐way ANOVA followed by Tukey's post hoc test (B, D, F). Scale bars, 200 μm (A, C) and 100 μm (E).

Article Snippet: This ECM is composed of various fibrous proteins including fibrillar collagens, fibronectin 1 (FN1), and fibulin 2 (FBLN2) (Brassart‐Pasco et al. ; Cox ).

Techniques: Migration, Transwell Migration Assay, Cell Adhesion Assay, Alternative Splicing

Journal: Scientific Reports

Article Title: LOX + iCAFs in HNSCC have the potential to predict prognosis and immunotherapy responses revealed by single cell RNA sequencing analysis

doi: 10.1038/s41598-025-91036-6

Figure Lengend Snippet: Expression pattern of LOX + iCAF-related signature and regulated the proliferation and migration of OSCC. (A, B) H&E and the co-expression of CXCL12, FBLN1 in HNSCC-1/-2/-3/-4 tissues examined by immunofluorescence staining. Blue indicating DAPI. Scale bar = 100 μm, 50 μm, 20 μm (C) The expression levels of Pro-LOX, FBLN1 in UM-SCC-1, NF and CAF-S5/-S6 examined by western blot ( n = 3 per group). GAPDH used as internal control. Left: representative images. Right: quantification analysis of Pro-LOX in different groups. (D) The expression levels of Pro-LOX, FBLN1 in CAF-S5/-S6 induced by transfection with si-LOX-1136 and si-LOX-1277 compared with si-NC ( n = 3 per group). Left: representative images. Right: quantification analysis of Pro-LOX in different groups. (E) Macrophages treated by CM-derived from CAF-S5/-S6 induced by transfection with si-NC, si-LOX-1136 and si-LOX-1277 and the expression of CD86 and iNOS was subjected to western blot. Up: representative images. Bottom: quantification analysis of CD86 in different groups. (F) The proliferation of CAL-27 and UM-SCC-1 treated by CM of CAF-S5/-S6 induced by transfection with si-NC, si-LOX-1136 and si-LOX-1277 examined by CCK8 assay ( n = 3 per group). (G) The migration abilities of CAL-27 and UM-SCC-1 treated by CM of CAF-S5/-S6 induced by transfection with si-NC, si-LOX-1136 and si-LOX-1277 examined by wound healing assay ( n = 3 per group) Scale bar = 200 μm. For blots source data, see Fig. S4. *** P < 0.001.

Article Snippet: Primary antibodies contained LOX (1:1000; ab174316, Abcam), FBLN1 (1:1000; 20425-1-AP, Proteintech), CD86 (1:1000; absin115477, Absin, Shanghai, China), iNOS (1:1000; abs155177, Absin), Phospho-CSF1R-Tyr723 (1:500; AP1075, Abclonal technology, Wuhan, China), CSF1R (1:500; #67455, Cell Signaling Technology, Danvers, MA, USA), Phospho-Akt-Ser473 (1:500; #4060, Cell Signaling Technology), Akt (1:1000; #9272, Cell Signaling Technology), E-cadherin (1:1000; ab314063, Abcam), N-cadherin (1:1000; ab76011, Abcam), vimentin (1:1000; 10366-1-AP, Proteintech), Fibroblast activation protein (FAP, 1:1000; #52818, Cell Signaling Technology), α-SMA (1:1000; ab7817, Abcam), GAPDH (1:5000; 10494-1-AP, Proteintech).

Techniques: Expressing, Migration, Immunofluorescence, Staining, Western Blot, Control, Transfection, Derivative Assay, CCK-8 Assay, Wound Healing Assay