Journal: Signal Transduction and Targeted Therapy
Article Title: Development of a leucine-rich repeat-containing protein 15-targeted radio-immunotheranostic approach to deplete pro-tumorigenic mechanisms and immunotherapy resistance
doi: 10.1038/s41392-025-02410-9
Figure Lengend Snippet: Specificity and biodistribution of DUNP19 in multiple mouse models with LRRC15 expressing tumors. a Representative PET images of s.c. SAOS2 osteosarcoma xenografts ( n = 4) obtained at different time points post i.v. administration of [ 64 Cu]Cu-DUNP19, highlighting high tumor uptake with minimal accumulation in normal tissues. In contrast, PET with the clinical bone scanning agent [ 18 F]-NaF showed low activity in tumor tissue, with the majority of the radiotracer dose observed in bone (Bn) and bladder (Bl). b In vivo assessment of LRRC15 targeting specificity by [ 177 Lu]Lu-DUNP19. At 48 h post i.v. injection, [ 177 Lu]Lu-DUNP19 displayed significantly higher uptake ( p = 0.001 and 0.005) in LRRC15+ U118MG (blue bar) and HuO9 (red bar) tumors compared to LRRC15- LNCaP tumors (light gray bar). The accumulation of non-specific [ 177 Lu]-IgG1 in LRRC15+ HuO9 tumors (light blue bar) was significantly lower than that of [ 177 Lu]Lu-DUNP19 ( p = 0.003; n = 4/group). c [ 177 Lu]Lu-DUNP19 tumor uptake in multiple s.c. tumor models at 72 h p.i., correlating with the LRRC15 expression level in the respective model. d , e Kinetics of [ 177 Lu]Lu-DUNP19 in healthy organs and LRRC15+ SAOS2 and HuO9 osteosarcoma lesions ( n = 4). Ex vivo tissue biodistributions of [ 177 Lu]Lu-DUNP19 obtained at multiple time points after i.v. injection showed a continuous decline in activity levels in healthy organs, but sustained uptake by malignant lesions. f , g Microanatomy of tumor tissues obtained from animals treated with fluorescently labeled DUNP19. Confocal images of s.c. HuO9 (LRRC15+ cancer cells) and HCC1954 (LRRC15- cancer cells/LRRC15+ stroma) tumors harvested at 72 h post- i.v. injection of AF594-DUNP19 (yellow). Tumor sections were co-stained for Actin (red), DNA (DAPI, blue) and LAMP1 (lysosomal marker, green). Images show that DUNP19 accumulates in the cellular cytoplasm and co-localized with LAMP1 indicating intracellular trafficking of the mAb to the lysosomal compartments (arrow) after binding membranous LRRC15
Article Snippet: U118MG (glioblastoma), U87MG (glioblastoma), RPMI7951 (melanoma), NCI-H196 (small cell lung cancer), HCC1954 (breast cancer), SAOS2 (osteosarcoma), U2OS (OS), Kasumi-2 (leukemia), Calu-1 (non-small-cell lung cancer), RCH-ACV (leukemia), MHH-Call-3 (leukemia), Hs737.T (giant cell sarcoma), HEK293T, LNCaP (prostate cancer), K7M2 (murine osteosarcoma) and MC38-luc (murine colorectal cancer) were purchased from ATCC.
Techniques: Expressing, Activity Assay, In Vivo, Injection, Ex Vivo, Labeling, Staining, Marker, Binding Assay
ATCC is a verified supplier 
ATCC manufactures this product 
![Specificity and biodistribution of DUNP19 in multiple mouse models with LRRC15 expressing tumors. a Representative PET images of s.c. SAOS2 osteosarcoma xenografts ( n = 4) obtained at different time points post i.v. administration of [ 64 Cu]Cu-DUNP19, highlighting high tumor uptake with minimal accumulation in normal tissues. In contrast, PET with the clinical bone scanning agent [ 18 F]-NaF showed low activity in tumor tissue, with the majority of the radiotracer dose observed in bone (Bn) and bladder (Bl). b In vivo assessment of LRRC15 targeting specificity by [ 177 Lu]Lu-DUNP19. At 48 h post i.v. injection, [ 177 Lu]Lu-DUNP19 displayed significantly higher uptake ( p = 0.001 and 0.005) in LRRC15+ <t>U118MG</t> (blue bar) and HuO9 (red bar) tumors compared to LRRC15- LNCaP tumors (light gray bar). The accumulation of non-specific [ 177 Lu]-IgG1 in LRRC15+ HuO9 tumors (light blue bar) was significantly lower than that of [ 177 Lu]Lu-DUNP19 ( p = 0.003; n = 4/group). c [ 177 Lu]Lu-DUNP19 tumor uptake in multiple s.c. tumor models at 72 h p.i., correlating with the LRRC15 expression level in the respective model. d , e Kinetics of [ 177 Lu]Lu-DUNP19 in healthy organs and LRRC15+ SAOS2 and HuO9 osteosarcoma lesions ( n = 4). Ex vivo tissue biodistributions of [ 177 Lu]Lu-DUNP19 obtained at multiple time points after i.v. injection showed a continuous decline in activity levels in healthy organs, but sustained uptake by malignant lesions. f , g Microanatomy of tumor tissues obtained from animals treated with fluorescently labeled DUNP19. Confocal images of s.c. HuO9 (LRRC15+ cancer cells) and HCC1954 (LRRC15- cancer cells/LRRC15+ stroma) tumors harvested at 72 h post- i.v. injection of AF594-DUNP19 (yellow). Tumor sections were co-stained for Actin (red), DNA (DAPI, blue) and LAMP1 (lysosomal marker, green). Images show that DUNP19 accumulates in the cellular cytoplasm and co-localized with LAMP1 indicating intracellular trafficking of the mAb to the lysosomal compartments (arrow) after binding membranous LRRC15](https://pub-med-central-images-cdn.bioz.com/pub_med_central_ids_ending_with_0655/pmc12480655/pmc12480655__41392_2025_2410_Fig2_HTML.jpg)
![Therapeutic efficacy of [ 177 Lu]Lu-DUNP19 in LRRC15-expressing human xenograft models. a , b BALB/c nude mice bearing s.c. U118MG GBM xenografts were treated with two fractions of [ 177 Lu]Lu-DUNP19 at days 0 and 34 for a cumulative activity of 20 MBq (10 + 10 MBq, red, n = 12) or 30 MBq (20 + 10 MBq, blue, n = 12) or left untreated ( n = 11). Despite lower LRRC15 expression by U118MG tumors, treatment with [ 177 Lu]Lu-DUNP19 significantly controlled tumor growth and prolonged survival (median survival; untreated = 78 days, 20 MBq = not reached, 30 MBq = not reached, p < 0.0001). c [ 177 Lu]Lu-DUNP19 is effective in HCC1954 breast cancer models (LRRC15- cancer cells, LRRC15+ stroma). Results demonstrate delayed s.c. HCC1954 growth in female mice intravenously administered a single dose of [ 177 Lu]Lu-DUNP19 (20 MBq; day 8, n = 10). d Median survival was not reached for the treated group by the end of the observation period (day 62), while median survival of control mice was 30.5 days ( p = 0.0001)](https://pub-med-central-images-cdn.bioz.com/pub_med_central_ids_ending_with_0655/pmc12480655/pmc12480655__41392_2025_2410_Fig4_HTML.jpg)
![[ 177 Lu]Lu-DUNP19 RIT induced signatures in LRRC15+ cancer cells. a Schematic of transcriptomic analysis of HuO9, U118MG, and HCC1954 tumors after [ 177 Lu]Lu-DUNP19 treatment (HuO9, untreated n = 6, treated n = 16; U118MG, untreated n = 8, treated n = 16; and HCC1954, untreated n = 8, treated n = 10). Treated or untreated tumor samples were harvested for RNA isolation, before sequencing and alignment to either murine or human genomes. Overlapping or ambiguous reads were discarded. b Volcano plot of the top up- (red) and downregulated (blue) DEGs after treatment with [ 177 Lu]Lu-DUNP19 in U118MG (left; n = 16) and HuO9 (right; n = 16) cancer cells (FDR < 0.05). DEGs were ranked by fold-change. The top and bottom genes were labeled. c , d Gene ontology (GO) biological pathway enrichment analysis of DEGs in treated ( c ) U118MG and ( d ) HuO9 cancer cells (adjusted p -value < 0.05). Enriched biological pathways with more than 10 overlapping terms (genes) were plotted by adjusted p -value value to indicate processes most significantly enriched after [177Lu]Lu-DUNP19 RIT](https://pub-med-central-images-cdn.bioz.com/pub_med_central_ids_ending_with_0655/pmc12480655/pmc12480655__41392_2025_2410_Fig5_HTML.jpg)
![[ 177 Lu]Lu-DUNP19 therapy decreases expression of a LRRC15 + TGFβ signature associated with immunotherapy resistance. a – c DEGs overlapped in [ 177 Lu]Lu-DUNP19-treated stroma from U118MG ( a , 26 genes; n = 16 tumors), HuO9 ( b , 23 genes; n = 16 tumors), and HCC1954 ( c , 26 genes; n = 10 tumors) tumors. Relative expression (Z-score normalization) was plotted to indicate upregulated (red) or downregulated (blue) genes. d Box-and-whisker plots representing relative transcript expression of LRRC15 (top) and TGFB1 (bottom), comparing untreated tumors to tumors after [ 177 Lu]Lu-DUNP19 therapy. HuO9 transcripts are plotted in red (left), U118MG in blue (middle), and HCC1954 in black (right). Samples were separated by transcript signature based on PCA plots and hierarchical clustering (Supplementary Fig. ) into 2 (HCC1954) or 3 (U118MG, HuO9) clusters. Expression of LRRC15 and TGFβ1 in treated samples from cluster 3 are significantly ( p < 0.005) decreased in U118MG and HuO9, while no changes are observed in the LRRC15- HCC1954 cancer cells. e , f Transcript data from clustered (Supplementary Fig. ) cancer cells ( e ) or tumor stroma ( f ) show decreased expression of the LRRC15+ TGFβ signature. e Untreated U118MG (top) and HuO9 (middle) cancer cells lose expression of the LRRC15 + TGFβ signature after [ 177 Lu]Lu-DUNP19 treatment (red = high, blue = low expression). f Loss of the LRRC15+ TGFβ signature is observed across all tumor stroma after [ 177 Lu]Lu-DUNP19 RIT (green = high, orange = low expression). g HCC1954 tumors that were resistant to [ 177 Lu]Lu-DUNP19 treatment (defined as reaching 1000 mm 3 endpoint before conclusion of study, n = 2) had no significant reduction of the 11-gene LRRC15+ TGFβ signature within tumor stroma ( p < 0.05)](https://pub-med-central-images-cdn.bioz.com/pub_med_central_ids_ending_with_0655/pmc12480655/pmc12480655__41392_2025_2410_Fig6_HTML.jpg)