Journal: Molecular Cancer
Article Title: Targeting the tumor cell-intrinsic ITGB2 axis inhibits melanoma progression
doi: 10.1186/s12943-025-02527-z
Figure Lengend Snippet: Melanoma cell-intrinsic ITGB2 expression and activation by CD44 ( A ) Single-cell (sc) RNA-seq analysis of human ITGB2 gene ( ITGB2 ) expression by patient melanoma (MM) cells versus tumor-infiltrating T cells or endothelial cells (ECs), as depicted by violin plots (median, bold white line; top and bottom quartiles, thin white lines) overlayed with dots representing respective single cells ( B ) Percentages (mean,) of human ITGB2 surface protein expression by patient MM cells, T cells, and ECs ( n = 5 patients) as determined by flow cytometry ( C ) Mean ITGB2 + SOX10 + frequency (%) in benign nevi ( n = 7 patients), primary melanomas ( n = 24 patients), and metastatic melanomas ( n = 13 patients) as determined by multicolor immunofluorescence staining of a patient melanocytic tissue microarray (TMA). Kruskal-Wallis multiple comparisons test was used to assess statistical significance ( D ) Incidence (%) of patient sentinel lymph node (SLN) metastases versus respective primary melanoma biospecimen cohorts ( n = 105) of increasing cancer cell-ITGB2 positivity, 0–2% ( n = 40), 2–25% ( n = 36), >25% ( n = 29), as determined by immunostaining. Frequencies of ITGB2-positive (black bars) and ITGB2-negative (white bars) melanoma cells within each cohort are shown. Fisher’s exact test was performed to determine statistical significance ( E ) Representative multiplex immunofluorescence staining of a patient primary melanoma biopsy for co-expression of ITGB2 (red, all panels) and the melanocytic marker, nuclear SOX-10 (green, first panel), pan T cell marker, CD3 (green, second panel), vascular endothelial marker, CD31 (green, third panel), or macrophage marker, PU.1 (green, fourth panel). Nuclei were counterstained with DAPI (blue). Size bars, 50 μm ( F and G ), Representative immunoblots of ITGB2 protein expression by (F) human melanoma lines, A2058, A375, C8161, FEMX, LOX-IMVI, MDA-MB-435S, and control HSB-2 T lymphoblastic leukemia cells and HUVEC endothelial cells, and (G) murine melanoma lines, B16-F10, YUMM1.7, YUMM3.3, YUMM4.1, YUMM5.2, and control EL-4 T cell lymphoma cells and C166 endothelial cells ( H and I ) Effect of CD44 ab-mediated crosslinking (black bars) versus isotype control ab treatment (white bars) on ITGB2 surface protein expression level (mean fluorescence intensity, MFI, ± SEM) by (H) human and (I) murine melanoma lines and respective cell controls (gray bars) as above, based on FC analysis ( J and K ) Effect of CD44 ab crosslinking as in (H and I) on the activation state of human melanoma cell-ITGB2 as determined by FC (MFI ± SEM) using the activation-sensitive ITGB2 antibody clones (J) KIM-127 and (K) MEM-148. Results are representative of at least n = 3 independent experiments. *, p < 0.05; **, p < 0.01; NS, not significant. See also figs. S1, S2, and S3.
Article Snippet: The following abs and reagents were used for immunohistochemistry and immunofluorescence: unconjugated mouse anti-human ITGB2 ab (clone MEM-48, Novus Biologicals, Cat# NB500-379, RRID: AB_10000712), Dako REAL Detection System, Alkaline Phosphatase/RED (Agilent Dako, Santa Clara, CA, Cat# K5005), Biotin-conjugated goat anti-mouse IgG (Thermo Fisher Scientific, Cat# 31800, RRID: AB_228305), AF546-conjugated goat anti-mouse IgG1 (Thermo Fisher Scientific, Cat# A-21123, RRID: AB_2535765), and AF488-conjugated goat anti-mouse IgG1 (Thermo Fisher Scientific, Cat# A-21121, RRID: AB_2535764), unconjugated rabbit anti-human SOX10 (clone EPR4007, Abcam, Cat# ab155279, RRID: AB_2650603), unconjugated rabbit anti-human CD3 (clone SP162, Abcam, Cat# ab135372, RRID: AB_2884903), unconjugated rabbit anti-human CD31 (clone EPR3094, Abcam, Cat# ab76533, RRID: AB_1523298), unconjugated rabbit anti-human ICAM-1 (MilliporeSigma, Cat# SAB5700809, RRID: AB_3669069) and Cy3-conjugated goat anti-rabbit IgG (Thermo Fisher Scientific, Cat# A10520, RRID: AB_10563288) or AF488-conjugated goat anti-rabbit IgG (Thermo Fisher Scientific, Cat# A-11008, RRID: AB_143165), unconjugated mouse anti-human SOX10 (clone 1D2C8, Proteintech, Rosemont, IL, Cat#66786-1-Ig, RRID: AB_2882131) and AF647-conjugated goat anti-mouse IgG2a (Thermo Fisher Scientific, Cat# A-21241, RRID: AB_2535810), unconjugated mouse anti-human PU.1 (clone G148-74, BD Biosciences, Cat# 554268, RRID: AB_395335) and AF488-conjugated goat anti-mouse IgG2a (Thermo Fisher Scientific, Cat# A-21131, RRID: AB_2535771).
Techniques: Expressing, Activation Assay, RNA Sequencing, Flow Cytometry, Multicolor Immunofluorescence Staining, Microarray, Immunostaining, Multiplex Assay, Immunofluorescence, Staining, Marker, Western Blot, Control, Fluorescence, Clone Assay