GPC3-targeted immunoPET imaging of hepatocellular carcinomas

Shuxian An; Di Zhang; You Zhang; Cheng Wang; Liang Shi; Weijun Wei; Gang Huang; Jianjun Liu

doi:10.1007/s00259-022-05723-x

GPC3-targeted immunoPET imaging of hepatocellular carcinomas

Eur J Nucl Med Mol Imaging. 2022 Jul;49(8):2682-2692. doi: 10.1007/s00259-022-05723-x. Epub 2022 Feb 11.

Authors

Shuxian An^#¹, Di Zhang^#¹, You Zhang¹, Cheng Wang¹, Liang Shi², Weijun Wei³, Gang Huang⁴, Jianjun Liu⁵

Affiliations

¹ Department of Nuclear Medicine, School of Medicine, Renji Hospital, Shanghai Jiao Tong University, 1630 Dongfang Rd, Shanghai, 200127, China.
² Department of Nuclear Medicine, Nanjing First Hospital, Nanjing Medical University, 68 Changle Rd, Nanjing, 210006, China.
³ Department of Nuclear Medicine, School of Medicine, Renji Hospital, Shanghai Jiao Tong University, 1630 Dongfang Rd, Shanghai, 200127, China. wwei@shsmu.edu.cn.
⁴ Department of Nuclear Medicine, School of Medicine, Renji Hospital, Shanghai Jiao Tong University, 1630 Dongfang Rd, Shanghai, 200127, China. huanggang@sumhs.edu.cn.
⁵ Department of Nuclear Medicine, School of Medicine, Renji Hospital, Shanghai Jiao Tong University, 1630 Dongfang Rd, Shanghai, 200127, China. nuclearj@163.com.

^# Contributed equally.

PMID: 35147737
DOI: 10.1007/s00259-022-05723-x

Abstract

Purpose: Early detection of hepatocellular carcinoma (HCC) remains a clinical challenge. Glypican 3 (GPC3) is a proteoglycan highly specific for HCC and is a potential diagnostic and therapeutic target for HCC. This work aims to develop GPC3-targeted immuno-positron emission tomography (immunoPET) imaging strategies and to assess the diagnostic values in preclinical HCC models.

Methods: Flow cytometry was used to screen GPC3-positive HCC cell lines. The expression of GPC3 in HCCs was detected by immunohistochemistry on tissue microarray. A novel GPC3-specific single domain antibody (sdAb) was produced and labeled with gallium-68 (⁶⁸Ga, T_1/2 = 1.1 h) and fluorine-18 (¹⁸F, T_1/2 = 1.8 h) to develop radiotracers with different half-lives. The diagnostic efficacies of the developed probes (i.e., [⁶⁸Ga]Ga-NOTA-G2, [¹⁸F]F-G2, and [⁶⁸Ga]Ga-NOTA-ABDG2) were interrogated in preclinical HCC models bearing varying GPC3 levels.

Results: GPC3 was strongly expressed on HCC cell lines and patients with poorly differentiated HCC. [⁶⁸Ga]Ga-NOTA-G2 immunoPET imaging specifically delineated the subcutaneous HCC lesions, outperforming the traditional ¹⁸F-fluorodeoxyglucose PET and the nonspecific [⁶⁸Ga]Ga-NOTA-NbGFP immunoPET. ImmunoPET imaging with [¹⁸F]F-G2 also efficiently diagnosed the tumors with clarity. Moreover, the fusion of G2 to an albumin-binding domain (ABD) significantly increased the tumor uptake and decreased kidney accumulation of the radiotracer when compared to [⁶⁸Ga]Ga-NOTA-G2.

Conclusions: In the work, we successfully developed sdAb-derived GPC3-targeted immunoPET imaging strategies and characterized the superior diagnostic accuracies in preclinical HCC models. Furthermore, we synthesized a fusion protein ABDG2 with improved targeting and pharmacokinetic properties, serving as a promising candidate for developing radioimmunotherapy agents.

Keywords: Companion diagnostics; Glypican 3 (GPC3); Hepatocellular carcinoma; ImmunoPET; Nanobody.

MeSH terms

Carcinoma, Hepatocellular* / diagnostic imaging
Carcinoma, Hepatocellular* / metabolism
Gallium Radioisotopes
Glypicans / chemistry
Glypicans / metabolism
Humans
Liver Neoplasms* / metabolism
Positron-Emission Tomography

Substances

GPC3 protein, human
Gallium Radioisotopes
Glypicans