TY - JOUR
T1 - Optimizing live-animal bioluminescence imaging prediction of tumor burden in human prostate cancer xenograft models in SCID-NSG mice
AU - Kim, Sangyub
AU - Zhang, Yong
AU - Tang, Suni
AU - Qin, Chongtao
AU - Karelia, Deepkamal
AU - Sharma, Arati
AU - Jiang, Cheng
AU - Lu, Junxuan
N1 - Funding Information:
The authors thank Charles Sawyers, MD, of Memorial Sloan Kettering Cancer Center, New York, NY, for the generous gift of the LNCaP-AR-luc cells. They thank laboratory of Patricia S. Steeg, PhD, National Cancer Institute, for providing MDA-MB-231-BR-luc2 cells. They thank Christopher Adkins, PhD and Paul Lockman, PhD, formerly of TTUHSC School of Pharmacy, for guidance and assistance with BLI for TX series of studies. The authors thank Bioluminescence Imaging Core (Sang Lee, PhD), Genome Sciences and Bioinformatics Core (Yuka Imamura, PhD), Flow Cytometry Core, and the laboratory of Keith Cheng, MD, PhD for use of Aperio Digital Pathology scanner for BLI studies in Penn State College of Medicine (PA-04 study). They thank Marianne Klinger of the Molecular and Histopathology Core of Penn State College of Medicine for IHC and H&E staining of the tumor tissues. The studies were supported by in parts by National Center for Complementary and Integrative Health (NCCIH) (grant no. R01AT007395) and National Cancer Institute (NCI) (grant no. R01 CA172169 and R21 CA218774).
Funding Information:
The studies were supported by in parts by National Center for Complementary and Integrative Health (NCCIH) (grant no. R01AT007395) and National Cancer Institute (NCI) (grant no. R01 CA172169 and R21 CA218774).
Publisher Copyright:
© 2019 Wiley Periodicals, Inc.
PY - 2019/6/15
Y1 - 2019/6/15
N2 - Background: Noninvasive live-animal longitudinal monitoring of xenograft tumor growth and metastasis by bioluminescent imaging (BLI) has been widely reported in cancer biology and preclinical therapy literature, mainly in athymic nude mice. Our own experience at calibrating BLI readout with tumor weight/volume in human prostate cancer xenograft models in haired, SCID-NSG mice through intraprostatic (orthotopic) and subcutaneous (SC) inoculations revealed either nonexistent or poor correlation (coefficient of determination, R 2 = ~0.01-0.3). The present work examined several technical and biological factors to improve BLI utility. Methods: After ruling out promoter-luciferase (luc) specificity and luc gene loss in the cell inoculum with LNCaP-AR-luc cells expressing an androgen receptor (AR) and tagged with AR-responsive probasin promoter-luc gene, we evaluated different routes of d-luciferin administration, imaging time during the day, charge-coupled device camera image acquisition settings, and hair removal methods to improve the imaging protocol. For most imaging sessions, BLI was carried out within the same day of tumor volume measurement. After necropsy, histological and immunohistochemical (IHC) analyses were performed on the tumors to evaluate necrosis and expression of luciferase and AR, respectively. Results: Injection of d-luciferin by SC route, robust image-capture setting (30 000 counts and autoexposure), imaging in the morning and thorough hair removal resulted in a substantial improvement of R2 to ~0.6. Histological analyses confirmed the lack of BLI signal in necrotic tumor masses consistent with luciferase-mediated light emission only in oxygenated adenosine triphosphate-producing viable cells. IHC staining detected heterogeneous expression of luciferase tracking generally with AR expression in nonnecrotic tumor tissues. Conclusions: Our body of work highlighted a framework to validate imaging protocols to ensure the acquisition of interpretable BLI data as an indicator of xenograft tumor burden. The vast tissue heterogeneity in prostate tumor xenografts and variable luciferase expression constrained this technology from achieving a high correlation.
AB - Background: Noninvasive live-animal longitudinal monitoring of xenograft tumor growth and metastasis by bioluminescent imaging (BLI) has been widely reported in cancer biology and preclinical therapy literature, mainly in athymic nude mice. Our own experience at calibrating BLI readout with tumor weight/volume in human prostate cancer xenograft models in haired, SCID-NSG mice through intraprostatic (orthotopic) and subcutaneous (SC) inoculations revealed either nonexistent or poor correlation (coefficient of determination, R 2 = ~0.01-0.3). The present work examined several technical and biological factors to improve BLI utility. Methods: After ruling out promoter-luciferase (luc) specificity and luc gene loss in the cell inoculum with LNCaP-AR-luc cells expressing an androgen receptor (AR) and tagged with AR-responsive probasin promoter-luc gene, we evaluated different routes of d-luciferin administration, imaging time during the day, charge-coupled device camera image acquisition settings, and hair removal methods to improve the imaging protocol. For most imaging sessions, BLI was carried out within the same day of tumor volume measurement. After necropsy, histological and immunohistochemical (IHC) analyses were performed on the tumors to evaluate necrosis and expression of luciferase and AR, respectively. Results: Injection of d-luciferin by SC route, robust image-capture setting (30 000 counts and autoexposure), imaging in the morning and thorough hair removal resulted in a substantial improvement of R2 to ~0.6. Histological analyses confirmed the lack of BLI signal in necrotic tumor masses consistent with luciferase-mediated light emission only in oxygenated adenosine triphosphate-producing viable cells. IHC staining detected heterogeneous expression of luciferase tracking generally with AR expression in nonnecrotic tumor tissues. Conclusions: Our body of work highlighted a framework to validate imaging protocols to ensure the acquisition of interpretable BLI data as an indicator of xenograft tumor burden. The vast tissue heterogeneity in prostate tumor xenografts and variable luciferase expression constrained this technology from achieving a high correlation.
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U2 - 10.1002/pros.23802
DO - 10.1002/pros.23802
M3 - Article
C2 - 30958914
AN - SCOPUS:85065755253
SN - 0270-4137
VL - 79
SP - 949
EP - 960
JO - Prostate
JF - Prostate
IS - 9
ER -
