In vivo imaging characterization and anticancer efficacy of a novel HER2 affibody and pemetrexed conjugate in lung cancer model

Advances in the Application of Radionuclide-Labeled HER2 Affibody for the Diagnosis and Treatment of Ovarian Cancer

Human epidermal growth factor receptor 2 (HER2) is a highly expressed tumor marker in epithelial ovarian cancer, and its overexpression is considered to be a potential factor of poor prognosis. Therefore, monitoring the expression of HER2 receptor in tumor tissue provides favorable conditions for accurate localization, diagnosis, targeted therapy, and prognosis evaluation of cancer foci. Affibody has the advantages of high affinity, small molecular weight, and stable biochemical properties. The molecular probes of radionuclide-labeled HER2 affibody have recently shown broad application prospects in the diagnosis and treatment of ovarian cancer; the aim is to introduce radionuclides into the cancer foci, display systemic lesions, and kill tumor cells through the radioactivity of the radionuclides. This process seamlessly integrates the diagnosis and treatment of ovarian cancer. Current research and development of new molecular probes of radionuclide-labeled HER2 affibody should focus on overcoming the deficiencies of non-specific uptake in the kidney, bone marrow, liver, and gastrointestinal tract, and on reducing the background of the image to improve image quality. By modifying the amino acid sequence; changing the hydrophilicity, surface charge, and lipid solubility of the affibody molecule; and using different radionuclides, chelating agents, and labeling conditions to optimize the labeling method of molecular probes, the specific uptake of molecular probes at tumor sites will be improved, while reducing radioactive retention in non-target organs and obtaining the best target/non-target value. These measures will enable the clinical use of radionuclide-labeled HER2 affibody molecular probes as soon as possible, providing a new clinical path for tumor-specific diagnosis, targeted therapy, and efficacy evaluation. The purpose of this review is to describe the application of radionuclide-labeled HER2 affibody in the imaging and treatment of ovarian cancer, including its potential clinical value and dilemmas.

A narrative review of advances in treatment and survival prognosis of HER2-positive malignant lung cancers

Human epidermal growth factor receptor 2 (HER2), as a receptor tyrosine kinase of EGF receptor family, whose mutation is often associated with even if less frequency but poor prognosis and shorter survival in pulmonary malignant tumor. HER2 status include mutation, overexpression, amplification and also some rare genotypes, detected by next generation sequencing (NGS), immunohistochemistry (IHC), and also fluorescence in situ hybridization (FISH). Different genotypes represent different therapeutic targets and indicate different clinical prognosis concluded by previous studies. Unfortunately, no standard guidelines for first-line treatment are widely recognized, and current therapeutic schedules include chemotherapy, radiotherapy, targeted therapy, and immunotherapy. Especially for patients with advanced metastasis, chemotherapy is based as a systemic therapy using studies of breast cancer or EGFR-positive lung adenocarcinoma as a template. Studies already explored treatment including EGFR tyrosine kinase inhibitors (TKIs) such as gefitinib and afatinib, and also trastuzumab and its conjugation like HER2-targeted antibody-drug conjugate trastuzumab emtansine (T-DM1) and conjugate trastuzumab deruxtecan (T-DXd). Also, he researches explored combination therapy with chemotherapy and TKIs or monoclonal antibodies. This review describes commonly used therapies for HER2-positive/HER2-overexpression patients and general relationship between genotypes of HER2, drug selection and final prognosis in order to provide suggestions for future diagnosis and treatment.

Preliminary Study of a 1,5-Benzodiazepine-Derivative Labelled with Indium-111 for CCK-2 Receptor Targeting

The cholecystokinin-2 receptor (CCK-2R) is overexpressed in several human cancers but displays limited expression in normal tissues. For this reason, it is a suitable target for developing specific radiotracers. In this study, a nastorazepide-based ligand functionalized with a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelator (IP-001) was synthesized and labelled with indium-111. The radiolabeling process yielded >95% with a molar activity of 10 MBq/nmol and a radiochemical purity of >98%. Stability studies have shown a remarkable resistance to degradation (>93%) within 120 h of incubation in human blood. The in vitro uptake of [¹¹¹In]In-IP-001 was assessed for up to 24 h on a high CCK-2R-expressing tumor cell line (A549) showing maximal accumulation after 4 h of incubation. Biodistribution and single photon emission tomography (SPECT)/CT imaging were evaluated on BALB/c nude mice bearing A549 xenograft tumors. Implanted tumors could be clearly visualized after only 4 h post injection (2.36 ± 0.26% ID/cc), although a high amount of radiotracer was also found in the liver, kidneys, and spleen (8.25 ± 2.21%, 6.99 ± 0.97%, and 3.88 ± 0.36% ID/cc, respectively). Clearance was slow by both hepatobiliary and renal excretion. Tumor retention persisted for up to 24 h, with the tumor to organs ratio increasing over-time and ending with a tumor uptake (1.52 ± 0.71% ID/cc) comparable to liver and kidneys.

Synthesis of a novel 99mTc labeled GE11 peptide for EGFR SPECT imaging

PURPOSE

This study investigated a novel SPECT agent for the noninvasive imaging of EGFR-overexpressing tumors.

METHODS

The EGFR-targeting peptide GE11 was synthesized with the introduction of four amino acids (GGGC) to its C-terminal to act as a strong chelator and radiolabeled using ^99mTc. The radiochemical yield of the ^99mTc-peptide-GE11 were evaluated using RP-HPLC. Cellular assays of the probe were performed on two NSCLC cell lines: A549 (high expression) and H23 (low expression). Biodistribution and SPECT imaging were performed in BALB/c nude mice bearing A549 and H23 NSCLC xenografts.

RESULTS

The ^99mTc-peptide-GE11 was prepared at high efficiency with radiochemical yield of 98.40 ± 1.00 % and it showed favorable stability. The cellular uptake was significantly higher in A549 than in H23 at all time points (especially at 1 h, which was 10.34 ± 0.72 and 2.04 ± 0.18, respectively). A nearly 56% reduction in probe uptake was observed after pretreatment with excess unlabeled peptides. The performance of SPECT imaging and biodistribution demonstrated higher uptake of the ^99mTc-peptide-GE11 in A549 xenograft than in H23 xenografts.

CONCLUSION

The new SPECT tracer ^99mTc-peptide-GE11 showed EGFR specificity, favorable pharmacokinetics and great potential for EGFR-targeted imaging.

Therapeutic efficacy and imaging assessment of the HER2-targeting chemotherapy drug ZHER2:V2-pemetrexed in lung adenocarcinoma Xenografts

Chemotherapy has always been the first therapeutic option for patients with advanced non-small cell lung cancer (NSCLC) with untreatable oncogenic mutations. However, chemotherapy has demonstrated limited success and is associated with severe side effects. This research aimed to investigate the antitumor efficacy and cytotoxic safety of the conjugate Z_HER2:V2-pemetrexed, a novel targeted chemotherapeutic drug. In this context, human epidermal growth factor receptor 2 (HER2) + A549 lung xenografts were treated using Z_HER2:V2-pemetrexed, pemetrexed or physiological saline. Therapeutic efficacy was monitored by single photon emission computed tomography (SPECT) imaging using the ^99mTc-labeled Z_HER2:V2-pemetrexed conjugate and further confirmed by performing apoptosis assays using flow cytometry analysis and hematoxylin-eosin (H&E) staining. To evaluate the expression of HER2 in tumor tissues, immunohistochemistry was performed, accompanied by quantitative analysis using flow cytometry. A toxicological evaluation was also conducted. Imaging with ^99mTc-Z_HER2:V2-pemetrexed demonstrated that in HER2+ A549 models, Z_HER2:V2-pemetrexed showed better antineoplastic effects than pemetrexed. Compared with pemetrexed, the results from the pathological and flow cytometry analyses also revealed that Z_HER2:V2-pemetrexed exhibits high antitumor activity against A549 tumors, inducing necrosis, apoptosis and cell cycle arrest. In addition, the clinical signs of toxicity in the Z_HER2:V2-pemetrexed treated group were reduced compared with those in the pemetrexed treated group. These data revealed that the Z_HER2:V2-pemetrexed conjugate encompasses promising targeted antitumor activity against HER2-positive lung adenocarcinoma, with reduced side effects compared with pemetrexed. Thus, the Z_HER2:V2-pemetrexed conjugate may serve as a novel molecular agent with tremendous clinical breakthrough potential in the diagnosis and treatment of HER2-positive lung adenocarcinoma.