Novel Radiolabeled TMTP1 for Long-Acting Hepatocellular Carcinoma Therapeutics.

Currently, the 5-year survival rate for patients with advanced hepatocellular carcinoma (HCC) is very low. Therefore, there is an urgent need to find new strategies for the treatment of HCC. TMTP1 (NVVRQ) is a tumor-homing peptide that has been shown to target a range of highly metastatic tumor cells. In this study, a novel radiotherapeutic probe, [177Lu]Lu-DOTA-EB-TMTP1, was synthesized and used to explore the antitumor efficacy in an HCC tumor model. The albumin-binding TMTP1 radioligand was achieved with >98% radiochemical purity. Long tumor retention property of [177Lu]Lu-DOTA-EB-TMTP1 was exhibited in single photon emission computed tomography (SPECT) imaging and biodistribution study. The [177Lu]Lu-DOTA-EB-TMTP1 showed significant accumulation in the SMMC-7721 HCC tumor with an uptake value of 9.67 ± 1.27 %ID/g at 8 h and a T/M ratio of 6.4. In radiotherapy studies, 30 days after injection of [177Lu]Lu-DOTA-EB-TMTP1, the tumor inhibition rate reached 93.2 ± 0.10 and 94.9 ± 0.04% in the 18.5 and 29.6 MBq high-dose groups, respectively. These preclinical data suggest that [177Lu]Lu-DOTA-EB-TMTP1 may be an effective treatment option for HCC and should be further evaluated in human trials.

Dual Targeting of Integrin αvß3 and Neuropilin-1 Receptors Improves Micropositron Emission Tomography Imaging of Breast Cancer.

The receptors neuropilin-1 (NRP-1) and integrin αvß3 are overexpressed in breast cancer and associated with neovascularization. We synthesized a heterodimeric tracer, 68Ga-DOTA-RGD-ATWLPPR, which simultaneously targets integrin αvß3 and NRP-1 in breast cancer. In this study, we evaluated the diagnostic efficacy of 68Ga-DOTA-RGD-ATWLPPR during micropositron emission tomography (microPET)/X-ray computed tomography (CT) imaging and gamma counting. We evaluated the receptor-binding characteristics and tumor-targeting efficacy of the tracer in vitro and in vivo. Static microPET/CT imaging and gamma counting studies showed that 68Ga-DOTA-RGD-ATWLPPR uptake in MCF-7 tumors is higher than that of monomeric tracers. 68Ga-DOTA-RGD-ATWLPPR uptake could be blocked with excess unlabeled RGD or ATWLPPR, demonstrating the sensitivity and specificity of the tracer. We did not observe bone tracer uptake in vivo, but the data indicated that 68Ga-DOTA-RGD-ATWLPPR is metabolized in the kidneys and the liver uptake is low. In conclusion, 68Ga-DOTA-RGD-ATWLPPR has improved binding affinity, targeting efficiency, and tumor retention time when compared to monomeric tracers, suggesting that it has potential as an imaging probe for breast cancer detection.

Imaging fibroblast activation protein in liver cancer: a single-center post hoc retrospective analysis to compare [68Ga]Ga-FAPI-04 PET/CT versus MRI and [18F]-FDG PET/CT.

PURPOSE: This study aimed to evaluate the potential utility of [68Ga]Ga-FAPI-04 PET/CT for diagnosing primary and metastatic lesions in patients with liver cancer, as well as to compare it with contrast-enhanced CT (CE-CT), liver MRI, and [18F]-FDG PET/CT. METHODS: We performed a single-center post hoc retrospective analysis of data obtained from a prospective parent study (NCT04416165). This study included 34 patients diagnosed with or suspected hepatic lesions who underwent concomitant [68Ga]Ga-FAPI-04 and [18F]-FDG/CT scans. Moreover, these patients underwent liver MRI (n = 34) and CE-CT (n = 25). Histopathologic (n = 62) or radiographic follow-up (n = 128) served as the reference standard for the final diagnosis. RESULTS: Among the 34 patients, 20, 12, and 2 patients presented with hepatocellular carcinomas, intrahepatic cholangiocarcinomas, and benign hepatic nodules, respectively. The sensitivities of CE-CT, MRI, [68Ga]Ga-FAPI-04, and [18F]-FDG/CT for detecting primary liver tumors were 96%, 100%, 96%, and 65%, respectively. Regarding the diagnosis of all intrahepatic lesions, the per-lesion detection rate of [68Ga]Ga-FAPI-04 PET/CT was slightly lower than that of MRI (85% vs. 100%, P = 0.34) and significantly higher than that of [18F]-FDG PET/CT (85% vs. 52%, P < 0.001). Regarding the diagnosis of all malignant lesions (including extrahepatic disease), the tumor detection rate of [68Ga]Ga-FAPI-04 PET/CT was 87.4%, which was significantly higher than that of [18F]-FDG PET/CT (65.0%, P < 0.001). CONCLUSIONS: Our findings indicate that the sensitivity of [68Ga]Ga-FAPI-04 PET/CT to correctly identify primary liver tumors and metastatic lesions is equivalent to that of CE-CT and liver MRI. Moreover, [68Ga]Ga-FAPI-04 PET/CT is better at identifying liver lesions than [18F]-FDG PET/CT, and its use may improve tumor staging, recurrence detection, and implementation of necessary treatment modifications.

Increased 68Ga-FAPI Uptake in Ankylosing Spondylitis in a Patient With Rectal Cancer.

ABSTRACT: Ankylosing spondylitis represents an inflammatory arthropathy with a predilection for the axial skeleton. We reported 68Ga-FAPI PET/CT finding of ankylosing spondylitis in a 65-year-old patient with rectal cancer. In addition to accumulating in primary tumor and metastatic lymph nodes, increased 68Ga-FAPI uptake was also observed in the sacroiliac and costovertebral joints, indicating sacroiliitis and spondylitis. However, no abnormal 18F-FDG uptake was observed in the inflammatory lesions. This case highlighted that 68Ga-FAPI PET/CT is useful for the evaluation of inflammatory conditions in ankylosing spondylitis.

A Paradigm of Cancer Immunotherapy Based on 2-[18F]FDG and Anti-PD-L1 mAb Combination to Enhance the Antitumor Effect.

PURPOSE: Efforts have been devoted to select eligible candidates for PD-1/PD-L1 immune checkpoint blocker (ICB) immunotherapy. Here, we have a serendipitous finding of positron emission tomography (PET) imaging tracer 2-[18F]FDG as a potential immunomodulator. Therefore, we hypothesize that 2-[18F]FDG could induce PD-L1 expression change and create an immune-favorable microenvironment for tumor immunotherapy. EXPERIMENTAL DESIGN: We designed a series of assays to verify PD-L1 upregulation, and tested immunotherapy regimens based on 2-[18F]FDG and anti-PD-L1 mAb, as monotherapy and in combination, in fully immunocompetent mice of MC38 and CT26 models. PD-L1 expression and tumor microenvironment (TME) changes were analyzed by Western blot, transcriptomics study, and flow-cytometric analysis. RESULTS: PD-L1 was upregulated in a time- and dose-dependent manner after being induced by 2-[18F]FDG. The activation of NF-κB/IRF3 pathway and STAT1/3-IRF1 pathway play crucial parts in modulating PD-L1 expression after DNA damage and repair. Improved αPD-L1 mAb utilization rate and significant tumor growth delay were observed when the personalized therapeutic alliance of 2-[18F]FDG stimulation and ICB was used. In addition, combination of 2-[18F]FDG with αPD-L1 mAb could reprogram a TME from "cold" to "hot," to make low immunoactivity tumors sensitive to ICB therapy. CONCLUSIONS: In summary, this promising paradigm has the potential to expand the traditional tumor theranostics. 2-[18F]FDG-based ICB immunotherapy is highly significant in enhancing antitumor effect. A research of 2-[18F]FDG-based ICB immunotherapy has been proposed to enhance the antitumor effect.

Comprehensive analysis reveals novel gene signature in head and neck squamous cell carcinoma: predicting is associated with poor prognosis in patients.

BACKGROUND: Head and neck squamous cell carcinoma (HNSC) remains an important public health problem, with classic risk factors being smoking and excessive alcohol consumption and usually has a poor prognosis. Therefore, it is important to explore the underlying mechanisms of tumorigenesis and screen the genes and pathways identified from such studies and their role in pathogenesis. The purpose of this study was to identify genes or signal pathways associated with the development of HNSC. METHODS: In this study, we downloaded gene expression profiles of GSE53819 from the Gene Expression Omnibus (GEO) database, including 18 HNSC tissues and 18 normal tissues. The differentially expressed genes (DEGs) were identified using the Linear Models for Microarray Data R package. Adjusted P values <0.01 and |log2 fold change (FC)| ≥2 was regarded as the filter condition. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of these DEGs were performed on the Database for Annotation, Visualization, and Integrated Discovery (DAVID) online website. Protein-protein interaction (PPI) network was built to visualize the interactions between these DEGs using the STRING online website. Finally, hub genes were identified by The Cancer Genome Atlas (TCGA) database. RESULTS: A total of 604 DEGs consisting of 159 upregulated genes and 445 downregulated genes were selected. From these DEGs, prognostic related genes could serve as potential biomarkers for the molecular diagnosis and therapeutic intervention of HNSC were identified. Including the known genes, GPR18, CNR2, RSPH4A, ULBP2, TEX101, and STC2. And the novel genes, CCR8, CCDC39, CNTN5, MSLN, and CHGB were strongly implicated in HNSC. CONCLUSIONS: In summary, we indicated genes associated with prognostic in patients, which improve our understanding of HNSC and could be used as new therapeutic targets for HNSC.

Syntheses and Preliminary Evaluation of Dual Target PET Probe [18F]-NOTA-Gly3- E (2PEG4-RGD-WH701) for PET Imaging of Breast Cancer.

PURPOSE: Tumor Necrosis Factor Receptor 1 (TNFR1) and integrin αvß3 receptor are overexpressed in breast cancer. We hypothesized that a peptide ligand recognizing both receptors in a single receptor-binding probe would be advantageous. Here, we developed a novel 18F-labeled fusion peptide probe [18F]-NOTA-Gly3- E(2PEG4-RGD-WH701) targeting dual receptors (TNFR1 and αvß3) and evaluated the diagnostic efficacy of this radioactive probe in both MDA-MB-231 and MCF-7 xenograft models in mice. METHODS: The NOTA-conjugated RGD-WH701 analog was radiolabeled with 18F using NOTA-AlF chelation method. We used two PEG4 molecules and Glutamic acid (Glu) to covalently link c(RGDyK) with WH701. Gly3 was also added to further improve the water solubility and pharmacokinetic properties of the probe. The expression of TNFR1 and Integrin αvß3 in MCF-7 and MDA-MB-231 cells was detected by western blot analysis and immunofluorescence staining. The tumor-targeting characteristics of [18F]-NOTA-Gly3-E(2PEG4-RGDWH701) were assessed in nude mice bearing MDA-MB-231 and MCF-7 xenografts. RESULTS: HPLC analysis of the product NOTA-G3-E (2P4-RGD-WH701) revealed a purity >95%. The yield after attenuation correction was approximately 33.5%±2.8% (n=5), and the radiochemical purity was above 95%. The MDA-MB-231 tumor uptake of [18F]-NOTA-Gly3-E(2PEG4-RGD-WH701) was 1.14±0.14%ID/g, as measured by PET at 40min postinjection (p.i.). In comparison, the tumor uptake of [18F]-NOTA-RGD and [18F]- NOTA-WH701 in MDA-MB-231 xenografts was 0.96±0.13%ID/g and 0.93±0.28%ID/g, respectively. The MCF-7 tumor uptake of [18F]-NOTA-Gly3-E(2PEG4-RGD-WH701) was 1.22±0.11%ID/g, as measured by PET at 40min postinjection (p.i.). In comparison, the tumor uptake of [18F]-NOTA-RGD and [18F]-NOTA-WH701 in MCF-7 xenografts was 0.99±0.18%ID/g and 0.57±0.08%ID/g, respectively. CONCLUSION: [18F]AlF-NOTA-Gly3-E(2PEG4-RGD-WH701) was successfully synthesized and labeled with 18F. The results from the microPET/CT and biodistribution studies of [18F]AlF-NOTA-Gly3-E(2PEG4-RGDWH701) showed that the tracer could specifically target TNFR1 and integrin αvß3 receptors.

Immuno-SPECT/PET imaging with radioiodinated anti-PD-L1 antibody to evaluate PD-L1 expression in immune-competent murine models and PDX model of lung adenocarcinoma.

OBJECTIVE: Accurate evaluation of tumor programmed death ligand 1 (PD-L1) expression can assist in predicting whether a patient will respond to anti-PD-L1 therapy. In this study, we aimed to develop stable radioiodinated PD-L1 antibodies that can be used for PD-L1 targeted SPECT/PET imaging. METHODS: Radioiodination was accomplished via a prosthetic group ([131I]SIB or [124I]SIB) to give radioiodinated anti-human PD-L1 and anti-mouse PD-L1 antibody (anti-PD-L1 and anti-PD-L1M). MicroSPECT/PET imaging and biodistribution of radioiodinated antibodies were studied in two immune-competent murine models (B16F10 and 4T1 syngeneic tumor models) and patient-derived xenograft (PDX) model of lung adenocarcinoma to evaluate the feasibility of identifying tumor PD-L1 expression. RESULTS: Radioiodinated PD-L1 antibodies had high radiochemical purity (>99%) and favorable stability in vivo. There was high uptake of [131I]SIB-anti-PD-L1M in both 4T1 and B16F10 syngeneic tumors when injected with 5.5 MBq radiotracers containing 200 µg anti-mouse-PD-L1. The presence of excess unlabeled anti-PD-L1 antibody increased [131I]SIB-anti-PD-L1M uptake in tumors. The highly specific PD-L1-positive tumor uptake detected by SPECT imaging indicated that radioiodinated antibody could be used for PD-L1 expression imaging. In addition, PET imaging of the PDX model was performed with [124I]SIB-anti-PD-L1, which showed high signal intensity in tumors and optimal contrast between tumor and muscle (tumor-to-muscle ratios at 6 h p.i. and 24 h p.i. were 2.5 and 5.3, respectively). CONCLUSIONS: This study provides an efficient strategy for synthesizing stable radioiodinated PD-L1 antibodies with excellent pharmacokinetics to identify PD-L1 expression in tumors.