Title: A NIR fluorescent smart probe for imaging tumor hypoxia

Abstract

Abstract Background Tumor hypoxia is a characteristic of paramount importance due to low oxygenation levels in tissue negatively correlating with resistance to traditional therapies. The ability to noninvasively identify such could provide for personalized treatment(s) and enhance survival rates. Accordingly, we recently developed an NIR fluorescent hypoxia‐sensitive smart probe ( NO ₂ ‐Rosol ) for identifying hypoxia via selectively imaging nitroreductase (NTR) activity, which could correlate to oxygen deprivation levels in cells, thereby serving as a proxy. We demonstrated proof of concept by subjecting a glioblastoma (GBM) cell line to extreme stress by evaluating such under radiobiological hypoxic ( p O ₂  ≤ ~0.5%) conditions, which is a far cry from representative levels for hypoxia for brain glioma ( p O ₂  = ~1.7%) which fluctuate little from physiological hypoxic ( p O ₂  = 1.0‐3.0%) conditions. Aim We aimed to evaluate the robustness, suitability, and feasibility of NO ₂ ‐Rosol for imaging hypoxia in vitro and in vivo via assessing NTR activity in diverse GBM models under relevant oxygenation levels ( p O ₂  = 2.0%) within physiological hypoxic conditions that mimic oxygenation levels in GBM tumor tissue in the brain. Methods We evaluated multiple GBM cell lines tomore » determine their relative sensitivity to oxygenation levels via measuring carbonic anhydrase IX (CAIX) levels, which is a surrogate marker for indirectly identifying hypoxia by reporting on oxygen deprivation levels and upregulated NTR activity. We evaluated for hypoxia via measuring NTR activity when employing NO ₂ ‐Rosol in in vitro and tumor hypoxia imaging studies in vivo. Results The GBM39 cell line demonstrated the highest CAIX expression under hypoxic conditions representing that of GBM in the brain. NO ₂ ‐Rosol displayed an 8‐fold fluorescence enhancement when evaluated in GBM39 cells ( p O ₂  = 2.0%), thereby establishing its robustness and suitability for imaging hypoxia under relevant physiological conditions. We demonstrated the feasibility of NO ₂ ‐Rosol to afford tumor hypoxia imaging in vivo via it demonstrating a tumor‐to‐background of 5 upon (i) diffusion throughout, (ii) bioreductive activation by NTR activity in, and (iii) retention within, GBM39 tumor tissue. Conclusion We established the robustness, suitability, and feasibility of NO ₂ ‐Rosol for imaging hypoxia under relevant oxygenation levels in vitro and in vivo via assessing NTR activity in GBM39 models.« less

Authors:

Hettie, Kenneth S.  ^[1];

• Search DOE PAGES for author "Hettie, Kenneth S."
• Search DOE PAGES for ORCID "0000-0002-0607-7944"

Klockow, Jessica L. ^[2]; Moon, Eui Jung ^[3]; Giaccia, Amato J. ^[3]; Chin, Frederick T. ^[2]

---

+ Show Author Affiliations

1. Department of Radiology Stanford University School of Medicine Stanford California USA, Department of Otolaryngology ‐ Head &, Neck Surgery Stanford University Stanford California USA
2. Department of Radiology Stanford University School of Medicine Stanford California USA
3. Department of Radiation Oncology Stanford University School of Medicine Stanford California USA

Publication Date:

Sat Apr 03 00:00:00 EDT 2021

Sponsoring Org.:

USDOE

OSTI Identifier:

1773937

Alternate Identifier(s):

OSTI ID: 1786146

Grant/Contract Number:  

DOE DE‐SC0008397

Resource Type:

Published Article

Journal Name:

Cancer Reports

Additional Journal Information:

Journal Name: Cancer Reports Journal Volume: 4 Journal Issue: 5; Journal ID: ISSN 2573-8348

Publisher:

Wiley Blackwell (John Wiley & Sons)

Country of Publication:

Country unknown/Code not available

Language:

English