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ABSTRACT: Purpose
As a promotor of tumor invasion and tumor microenvironment (TME) formation, the protein complex S100A8/S100A9 is associated with poor prognosis. Our aim was to further evaluate its origin and regulatory effects, and to establish an imaging biomarker for TME activity.Methods
S100A9-/-cells (ko) were created from syngeneic murine breast cancer 4T1 (high malignancy) and 67NR (low malignancy) wildtype (wt) cell lines and implanted into either female BALB/c wildtype or S100A9-/- mice (n = 10 each). Anti-S100A9-Cy5.5-targeted fluorescence reflectance imaging was performed at 0 h and 24 h after injection. Potential early changes of S100A9-presence under immune checkpoint inhibition (anti-PD-L1, n = 7 vs. rat IgG2b as isotype control, n = 3) were evaluated.Results
In S100A9-/-mice contrast-to-noise-ratios were significantly reduced for wt and S100A9-/-tumors. No significant differences were detected for 4T1 ko and 67NR ko cells as compared to wildtype cells. Under anti-PD-L1 treatment S100A9 presence significantly decreased compared with the control group.Conclusion
Our results confirm a secretion of S100A8/S100A9 by the TME, while tumor cells do not apparently release the protein. Under immune checkpoint inhibition S100A9-imaging reports an early decrease of TME activity. Therefore, S100A9-specific imaging may serve as an imaging biomarker for TME formation and activity.
SUBMITTER: Helfen A
PROVIDER: S-EPMC8983428 | biostudies-literature | 2022 Jun
REPOSITORIES: biostudies-literature
Helfen Anne A Rieß Jan J Fehler Olesja O Stölting Miriam M An Zhengwen Z Kocman Vanessa V Schnepel Annika A Geyer Christiane C Gerwing Mirjam M Masthoff Max M Vogl Thomas T Höltke Carsten C Roth Johannes J Ng Tony T Wildgruber Moritz M Eisenblätter Michel M
Neoplasia (New York, N.Y.) 20220331
<h4>Purpose</h4>As a promotor of tumor invasion and tumor microenvironment (TME) formation, the protein complex S100A8/S100A9 is associated with poor prognosis. Our aim was to further evaluate its origin and regulatory effects, and to establish an imaging biomarker for TME activity.<h4>Methods</h4>S100A9<sup>-/-</sup>cells (ko) were created from syngeneic murine breast cancer 4T1 (high malignancy) and 67NR (low malignancy) wildtype (wt) cell lines and implanted into either female BALB/c wildtype ...[more]