24 research outputs found
Antisense oligonucleotide and thyroid hormone conjugates for obesity treatment
Using the principle of antibody-drug conjugates that deliver highly potent cytotoxic agents to
cancer cells for cancer therapy, we here report the synthesis of antisense-oligonucleotides (ASO) and thyroid hormone T3 conjugates for obesity treatment. ASOs primarily target fat and liver with poor penetrance to other organs. Pharmacological T3 treatment increases energy expenditure and causes weight loss, but is contraindicated for obesity treatment due to systemic effects on multiple organs. We hypothesize that ASO-T3 conjugates may knock down target genes and enrich T3 action in fat and liver. Two established ASOs are tested. Nicotinamide N-methyltransferase (NNMT)-ASO prevents diet- induced obesity in mice. Apolipoprotein B (ApoB)-ASO is an FDA approved drug for treating familial hypercholesterolemia. NNMT-ASO and ApoB-ASO are chemically conjugated with T3 using a non- cleavable sulfo-SMCC linker. Both NNMT-ASO-T3 (NAT3) and ApoB-ASO-T3 (AAT3) enhance thyroid hormone receptor activity. Treating obese mice with NAT3 or AAT3 decreases adiposity and increases lean mass. ASO-T3 enhances white fat browning, decreases genes for fatty acid synthesis in liver,
and shows limited effects on T3 target genes in heart and muscle. Furthermore, AAT3 augments LDL cholesterol-lowering effects of ApoB-ASO. Therefore, ASO and hormone/drug conjugation may provide a novel strategy for obesity and hyperlipidemia treatment
Dual-Labeling Strategies for Nuclear and Fluorescence Molecular Imaging: A Review and Analysis
Molecular imaging is used for the detection of biochemical processes through the development of target-specific contrast agents. Separately, modalities such as nuclear and near-infrared fluorescence (NIRF) imaging have been shown to non-invasively monitor disease. More recently, merging of these modalities has shown promise owing to their comparable detection sensitivity and benefited from the development of dual-labeled imaging agents. Dual-labeled agents hold promise for whole-body and intraoperative imaging and could bridge the gap between surgical planning and image-guided resection with a single, molecularly targeted agent. In this review, we summarized the literature for dual-labeled antibodies and peptides that have been developed and have highlighted key considerations for incorporating NIRF dyes into nuclear labeling strategies. We also summarized our findings on several commercially available NIRF dyes and offer perspectives for developing a toolkit to select the optimal NIRF dye and radiometal combination for multimodality imaging
Evaluation of Anti-LGR5 Antibodies by ImmunoPET for Imaging Colorectal Tumors and Development of Antibody–Drug Conjugates
Leucine-rich repeat-containing G-protein
coupled receptor 5 (LGR5)
is highly expressed in colorectal tumors and marks colon cancer stem
cells that drive tumor growth and metastasis. Recently, we showed
that LGR5 is a promising target for antibody–drug conjugate
(ADC) therapy. However, it is important to identify LGR5-positive
tumors that would respond to ADC treatment. Prior to drug conjugation,
we evaluated two different anti-LGR5 monoclonal antibodies (mAbs),
8F2 and 9G5, using <sup>89</sup>Zr-immunoPET to select the optimal
mAb for ADC development and tumor imaging. Binding, specificity, and
internalization were compared, and mAbs were prescreened as ADC candidates
against colon cancer cells using secondary ADCs. Both mAbs demonstrated
strong, specific binding in 293T-LGR5 cells but not 293T-vector cells.
In DLD-1 colorectal cancer cells, which express high levels of LGR5,
the mAbs rapidly internalized into lysosomes and promoted ADC-induced
cytotoxicity, with 8F2 exhibiting slightly higher potency. No binding
was detected in DLD-1-shLGR5 (LGR5 knockdown) cells. <sup>89</sup>Zr-DFO-LGR5 mAbs were generated and shown to retain high affinity
and LGR5-dependent uptake in vitro. PET/CT imaging of DLD-1 tumors
was performed 5 days postinjection of <sup>89</sup>Zr-DFO-LGR5 mAbs,
and findings were consistent with biodistribution data, which showed
significantly higher tumor uptake (%ID/g) for <sup>89</sup>Zr-DFO-8F2
(17.9 ± 2.2) compared to <sup>89</sup>Zr-DFO-9G5 (5.5 ±
1.2) and <sup>89</sup>Zr-DFO-IgG (3.8 ± 1.0). No significant
uptake was observed in DLD-1-shLGR5 tumors. This study identifies
8F2 as the optimal candidate for ADC development and provides initial
evidence that <sup>89</sup>Zr-DFO-LGR5 mAbs may be utilized to stratify
tumors which would respond best to LGR5-targeted ADC therapy
Establishment of Novel Neuroendocrine Carcinoma Patient-Derived Xenograft Models for Receptor Peptide-Targeted Therapy
Gastroenteropancreatic neuroendocrine neoplasms (GEP NENs) are rare cancers consisting of neuroendocrine carcinomas (NECs) and neuroendocrine tumors (NETs), which have been increasing in incidence in recent years. Few cell lines and pre-clinical models exist for studying GEP NECs and NETs, limiting the ability to discover novel imaging and treatment modalities. To address this gap, we isolated tumor cells from cryopreserved patient GEP NECs and NETs and injected them into the flanks of immunocompromised mice to establish patient-derived xenograft (PDX) models. Two of six mice developed tumors (NEC913 and NEC1452). Over 80% of NEC913 and NEC1452 tumor cells stained positive for Ki67. NEC913 PDX tumors expressed neuroendocrine markers such as chromogranin A (CgA), synaptophysin (SYP), and somatostatin receptor-2 (SSTR2), whereas NEC1452 PDX tumors did not express SSTR2. Exome sequencing revealed loss of TP53 and RB1 in both NEC tumors. To demonstrate an application of these novel NEC PDX models for SSTR2-targeted peptide imaging, the NEC913 and NEC1452 cells were bilaterally injected into mice. Near infrared-labelled octreotide was administered and the fluorescent signal was specifically observed for the NEC913 SSTR2 positive tumors. These 2 GEP NEC PDX models serve as a valuable resource for GEP NEN therapy testing
Establishment of Novel Neuroendocrine Carcinoma Patient-Derived Xenograft Models for Receptor Peptide-Targeted Therapy
Gastroenteropancreatic neuroendocrine neoplasms (GEP NENs) are rare cancers consisting of neuroendocrine carcinomas (NECs) and neuroendocrine tumors (NETs), which have been increasing in incidence in recent years. Few cell lines and pre-clinical models exist for studying GEP NECs and NETs, limiting the ability to discover novel imaging and treatment modalities. To address this gap, we isolated tumor cells from cryopreserved patient GEP NECs and NETs and injected them into the flanks of immunocompromised mice to establish patient-derived xenograft (PDX) models. Two of six mice developed tumors (NEC913 and NEC1452). Over 80% of NEC913 and NEC1452 tumor cells stained positive for Ki67. NEC913 PDX tumors expressed neuroendocrine markers such as chromogranin A (CgA), synaptophysin (SYP), and somatostatin receptor-2 (SSTR2), whereas NEC1452 PDX tumors did not express SSTR2. Exome sequencing revealed loss of TP53 and RB1 in both NEC tumors. To demonstrate an application of these novel NEC PDX models for SSTR2-targeted peptide imaging, the NEC913 and NEC1452 cells were bilaterally injected into mice. Near infrared-labelled octreotide was administered and the fluorescent signal was specifically observed for the NEC913 SSTR2 positive tumors. These 2 GEP NEC PDX models serve as a valuable resource for GEP NEN therapy testing