Tumor necrosis targeted radiotherapy of non-small cell lung cancer using radioiodinated protohypericin in a mouse model

Three-Dimensional-Bioprinted Non-Small Cell Lung Cancer Models in a Mouse Phantom for Radiotherapy Research

Lung cancer continues to have one of the highest morbidity and mortality rates of any cancer. Although radiochemotherapy, in combination with immunotherapy, has significantly improved overall survival, new treatment options are urgently needed. However, preclinical radiotherapy testing is often performed in animal models, which has several drawbacks, including species-specific differences and ethical concerns. To replace animal models, this study used a micro-extrusion bioprinting approach to generate a three-dimensional (3D) human lung cancer model consisting of lung tumor cells embedded in human primary lung fibroblasts for radiotherapy research. The models were placed in a mouse phantom, i.e., a 3D-printed mouse model made of materials that mimic the X-ray radiation attenuation rates found in mice. In radiotherapy experiments, the model demonstrated a selective cytotoxic effect of X-rays on tumor cells, consistent with findings in 2D cells. Furthermore, the analysis of metabolic activity, cell death, apoptosis, and DNA damage-induced γH2AX foci formation revealed different results in the 3D model inside the phantom compared to those observed in irradiated models without phantom and 2D cells. The proposed setup of the bioprinted 3D lung model inside the mouse phantom provides a physiologically relevant model system to study radiation effects.

Radionuclide-based theranostics - a promising strategy for lung cancer

PURPOSE

This review aims to provide a comprehensive overview of the latest literature on personalized lung cancer management using different ligands and radionuclide-based tumor-targeting agents.

BACKGROUND

Lung cancer is the leading cause of cancer-related deaths worldwide. Due to the heterogeneity of lung cancer, advances in precision medicine may enhance the disease management landscape. More recently, theranostics using the same molecule labeled with two different radionuclides for imaging and treatment has emerged as a promising strategy for systemic cancer management. In radionuclide-based theranostics, the target, ligand, and radionuclide should all be carefully considered to achieve an accurate diagnosis and optimal therapeutic effects for lung cancer.

METHODS

We summarize the latest radiotracers and radioligand therapeutic agents used in diagnosing and treating lung cancer. In addition, we discuss the potential clinical applications and limitations associated with target-dependent radiotracers as well as therapeutic radionuclides. Finally, we provide our views on the perspectives for future development in this field.

CONCLUSIONS

Radionuclide-based theranostics show great potential in tailored medical care. We expect that this review can provide an understanding of the latest advances in radionuclide therapy for lung cancer and promote the application of radioligand theranostics in personalized medicine.

Neutrophil infiltration combined with necrosis in the primary tumor is a useful prognostic indicator for three‑year disease‑free survival time in patients with colorectal cancer

Histopathological evaluation plays a key role in the diagnosis of colorectal cancer (CRC). Tumor-related local inflammation is regarded as a novel prognostic parameter. Neutrophils constitute one of the main types of inflammatory cells. The aim of the present study was to evaluate the prognostic value of intratumoral tumor-associated neutrophils (intraTANs), stromal TANs (stromaTANs) and necrosis, as well as their combined parametric value in formalin-fixed paraffin-embedded tissue sections from patients with CRC. For this purpose, a retrospective study of 160 patients with CRC who underwent surgery was conducted. The association of intraTANs, stromaTANs, necrosis and their combined parametric value with the clinicopathological features of patients with CRC was examined. The Kaplan-Meier method and the log-rank test were used to compare survival curves. To identify independent prognostic factors, uni- and multivariate Cox proportional hazards regression models were used. StromaTANs were associated with lymph node metastasis (P=0.049) and tumor deposits (P=0.041). In addition, necrosis was found to be associated with venous (P=0.003), lymphatic (P=0.007) and perineural (P=0.015) invasion, as well as with lymph node metastasis (P=0.033), the number of invaded lymph nodes (P=0.012), and lymph node pouch invasion (P=0.043). Furthermore, necrosis was found to be associated with the white blood cell count (P=0.030), neutrophil count (P=0.011), the combined neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (NLR-PLR) (P=0.038), and the combined platelet and NLR (PLT-NLR status) (P=0.030), as well as with the serum carcinoembryonic antigen (CEA) levels following surgery (P=0.011) and the monocyte-to-lymphocyte ratio (P=0.023). The combined parametric value was found to be associated with pT stage (P=0.049), venous (P=0.034) and lymphatic (P=0.026) invasion, and with serum CEA levels prior to surgery (P=0.029). The analysis of the 3-year disease-free survival (DFS) time revealed that tumor growth [hazard ratio (HR), 2.070; 95% CI, 1.837-3.808; P=0.003] and the combined parametric value (intraTANs, stromaTANs and necrosis, HR, 1.577; 95% CI, 1.372-3.032; P=0.028) were independent factors for patients with CRC. Taken together, the findings of the present study demonstrated that the combined value of neutrophils and necrosis examined in the cancerous tissue may be used as a prognostic factor for the 3-year DFS time in patients with CRC.

Application and Importance of Theranostics in the Diagnosis and Treatment of Cancer

The number of cancer cases worldwide in terms of morbidity and mortality is a serious concern, despite the presence of therapeutic interventions and supportive care. Limitations in the current available diagnosis methods and treatments methods may contribute to the increase in cancer mortality. Theranostics, is a novel approach that has opened avenues for the simultaneous precise diagnosis and treatment for cancer patients. Although still in the early development stage, theranostic agents such as quantum dots, radioisotopes, liposomes and plasmonic nanobubbles can be bound to anticancer drugs, cancer cell markers and imaging agents, with the support of available imaging techniques, provide the potential to facilitate diagnosis, treatment and management of cancer patients. Herein, we discuss the potential benefits of several theranostic tools for the management of cancer. Specifically, quantum dots, radio-labelled isotopes, liposomes and plasmonic nanobubbles coupled with targeting agents and/or anticancer molecules and imaging agents as theranostic agents are deliberated upon in this review. Overall, the use of theranostic agents shows promise in cancer management. Nevertheless, intensive research is required to realize these expectations.

Discovery of necrosis avidity of rhein and its applications in necrosis imaging

Necrosis-avid agents possess exploitable theragnostic utilities including evaluation of tissue viability, monitoring of therapeutic efficacy as well as diagnosis and treatment of necrosis-related disorders. Rhein (4,5-dihydroxyl-2-carboxylic-9,10-dihydrodiketoanthracene), a naturally occurring monomeric anthraquinone compound extensively found in medicinal herbs, was recently demonstrated to have a newly discovered necrosis-avid trait and to show promising application in necrosis imaging. In this overview, we present the discovering process of rhein as a new necrosis-avid agent as well as its potential imaging applications in visualisation of myocardial necrosis and early evaluation of tumour response to therapy. Moreover, the molecular mechanism exploration of necrosis avidity behind rhein are also presented. The discovery of necrosis avidity with rhein and the development of rhein-based molecular probes may further expand the scope of necrosis-avid compounds and highlight the potential utility of necrosis-avid molecular probes in necrosis imaging.

Involvement of ER stress and reactive oxygen species generation in anti-cancer effect of CKD-516 for lung cancer

PURPOSE

CKD-516 (Valecobulin), a vascular-disrupting agent, inhibits microtubule elongation. We evaluated the effect of CKD-516 on lung cancer cells and the underlying molecular mechanisms.

METHODS

The effects of S516, an active metabolite of CKD-516, were evaluated in HUVECs and three lung cancer cell lines and by a microtubule polymerization assay. Tubulin cross-linking was used to identify the binding site of S516 on tubulin, and Western blotting was performed to identify the intracellular pathways leading to cell death. Subcutaneous lung cancer xenograft models were used to assess the in vivo effect of CKD-516 on tumor growth.

RESULTS

S516 targeted the colchicine binding site on β-tubulin. In lung cancer cells, S516 increased endoplasmic reticulum (ER) stress and induced reactive oxygen species (ROS) generation by mitochondria and the ER. In addition, CKD-516 monotherapy strongly inhibited the growth of lung cancer xenograft tumors and exerted a synergistic effect with carboplatin.

CONCLUSION

The findings suggest that CKD-516 exerts an anticancer effect in company with inducing ER stress and ROS production via microtubule disruption in lung cancer cells. CKD-516 may thus have therapeutic potential for lung cancer.

Updated developments on molecular imaging and therapeutic strategies directed against necrosis

Cell death plays important roles in living organisms and is a hallmark of numerous disorders such as cardiovascular diseases, sepsis and acute pancreatitis. Moreover, cell death also plays a pivotal role in the treatment of certain diseases, for example, cancer. Noninvasive visualization of cell death contributes to gained insight into diseases, development of individualized treatment plans, evaluation of treatment responses, and prediction of patient prognosis. On the other hand, cell death can also be targeted for the treatment of diseases. Although there are many ways for a cell to die, only apoptosis and necrosis have been extensively studied in terms of cell death related theranostics. This review mainly focuses on molecular imaging and therapeutic strategies directed against necrosis. Necrosis shares common morphological characteristics including the rupture of cell membrane integrity and release of cellular contents, which provide potential biomarkers for visualization of necrosis and necrosis targeted therapy. In the present review, we summarize the updated joint efforts to develop molecular imaging probes and therapeutic strategies targeting the biomarkers exposed by necrotic cells. Moreover, we also discuss the challenges in developing necrosis imaging probes and propose several biomarkers of necrosis that deserve to be explored in future imaging and therapy research.

Biodistribution and tolerance of intravenous iodine-131-labelled hypericin in healthy dogs

Hypericin (Hyp) is a necrosis-avid compound that can be efficiently labelled with radioiodine for both diagnostic and therapeutic purposes. Before ¹³¹ I-Hyp can be considered as a clinically useful drug in a combination therapy for canine cancer patients, evaluation of its toxicity is necessary. The aim of this study was to investigate the biodistribution and tolerance of a single dose administration of ¹³¹ I-Hyp. Three healthy dogs were included. ¹³¹ I-Hyp at a dose of 0.2 mg/kg and an activity of 185 MBq was intravenously injected. The effects on physical, haematological and biochemical parameters were characterized and the biodistribution and elimination pattern, the effective half-life and dose rate were assessed. Drug-related adverse events were limited to mild gastrointestinal signs, resolving within 48 hours. No significant differences were found in blood haematology and serum biochemistry before and after treatment. Following administration, highest percentage of injected dose (%ID ± SD) was found in the liver (5.5 ± 0.33), the lungs (4.17 ± 0.14) and the heart (3.11 ± 0.78). After 24 hours, highest %ID was found in colon (4.25 ± 1.45) and liver (3.45 ± 0.60). Clearance from all organs was effective within 7 days. Effective half-life was established at 80 hours, and the dose rate fell below <20 μSv/h at 1 m within 1 day. The current study reveals that single dose treatment with ¹³¹ I-Hyp at the described dose is well tolerated by healthy dogs and supports the use of radioiodinated hypericin in a combination therapy for canine cancer patients.

The vascular disrupting agent combretastatin A-4 phosphate causes prolonged elevation of proteins involved in heme flux and function in resistant tumor cells

Vascular disrupting agents (VDAs) represent a promising class of anti-cancer drugs for solid tumor treatment. Here, we aim to better understand the mechanisms underlying tumor reccurrence and treatment resistance following the administration of a VDA, combretastatin A-4 phosphate (CA4P). Firstly, we used photoacoustic tomography to noninvasively map the effect of CA4P on blood oxygen levels throughout subcutaneous non-small cell lung cancer (NSCLC) tumors in mice. We found that the oxygenation of peripheral tumor vessels was significantly decreased at 1 and 3 hours post-CA4P treatment. The oxygenation of the tumor core reduced significantly at 1 and 3 hours, and reached anoxia after 24 hours. Secondly, we examined the effect of CA4P on the levels of proteins involved in heme flux and function, which are elevated in lung tumors. Using immunohistochemistry, we found that CA4P substantially enhanced the levels of enzymes involved in heme biosynthesis, uptake, and degradation, as well as oxygen-utilizing hemoproteins. Furthermore, measurements of markers of mitochondrial function suggest that CA4P did not diminish mitochondrial function in resistant tumor cells. These results suggest that elevated levels of heme flux and function contribute to tumor regrowth and treatment resistance post-VDA administration.

Immune activity and biodistribution of polypeptide K237 and folic acid conjugated amphiphilic PEG-PLGA copolymer nanoparticles radiolabeled with 99mTc

In a previous study, amphiphilic copolymer, polypeptide K237 (HTMYYHHYQHHL) and folic acid (FA) modified poly(ethylene glycol)-poly(lactic-co-glycolic acid) (K237/FA-PEG-PLGA) nanoparticles were developed and studied as a drug carrier. To further promote the clinical application of K237/FA-PEG-PLGA nanoparticles and provide guidance for future research, we need to examine their specific biodistribution in vivo. In this study, K237/FA-PEG-PLGA nanoparticles were effectively labeled by a direct method with Technetium-99m (99mTc) using stannous chloride as a reducing agent. The optimal stability of the labeled nanoparticles was determined by evaluating their radiochemical purity in serum, physiological saline, diethylenetriaminepentaacetic acid (DTPA) and cysteine solutions. The affinity of ligands and receptors was elicited by cell binding and blocking experiments in KDR/folate receptor high expressing SKOV-3 ovarian cancer cells. The nanoparticles biodistribution was studied after intravenous administration in healthy mice xenografted with SKOV-3 cells. A higher percent injected dose per gram of tissue (% ID/g) was observed in liver, kidney, spleen, blood and tumor at 3 and 9 h post-injection. Scintigraphic images revealed that the radioactivity was mainly concentrated in tumor, liver, kidney and bladder; and in the heart, lung, and muscle was significantly lower at 3 h. The radioactivity distribution in the images is consistent with the in vivo biodistribution data. Our works demonstrated that K237/FA-PEG-PLGA nanoparticles have great potential as biodegradable drug carriers, especially for tumors expressing the folate and KDr receptor.

In vitroAnticancer Activities of Some Triterpene Glycosides from Holothurians of Cucumariidae, Stichopodidae, Psolidae, Holothuriidae and Synaptidae families

Triterpene glycosides isolated from holothurians are natural products known to possess cytotoxic properties against cancer cells. However, their anticancer prophylactic activity has not been studied sufficiently. The anticancer prophylactic, cytotoxic, and pro-apoptotic properties of 18 triterpene glycosides, as well as their effects on the transcriptional activities of activator protein-1 (AP-1) and nuclear factor-κB (NF-κB), were examined using methods that included EGF-induced JB6 Cl41 P+ cell transforation in soft agar, flow cytometry, MTS assessment of cell viability, and a luciferase activity assay. The compounds inhibited EGF-induced neoplastic JB6 Cl41 P+ cell transforation in soft agar and caused apoptosis and necrosis of human HL-60 and THP-1 leukemia cells. AP-1 and NF-κB were involved in the cellular response to the treatment by the compounds. Conclusion: glycosides isolated from holothurians of Cucumariidae, Stichopodidae, Psolidae, Holothuriidae and Synaptidae families have potential for development as new antitumor agents and as instruments to study AP-1 and NF-κB.

Optimal definition of biological tumor volume using positron emission tomography in an animal model

Background

The goal of the study is to investigate ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG-PET)’s ability to delineate the viable portion of a tumor in an animal model using cross-sectional histology as the validation standard.

Methods

Syngeneic mammary tumors were grown in female Lewis rats. Macroscopic histological images of the transverse tumor sections were paired with their corresponding FDG micro-PET slices of the same cranial-caudal location to form 51 pairs of co-registered images. A binary classification system based on four FDG-PET tumor contouring methods was applied to each pair of images: threshold based on (1) percentage of maximum tumor voxel counts (C_max), (2) percentage of tumor peak voxel counts (C_peak), (3) multiples of liver mean voxel counts (C_liver) derived from PERCIST, and (4) an edge-detection-based automated contouring system. The sensitivity, which represented the percentage of viable tumor areas correctly delineated by the gross tumor area (GTA) generated from a particular tumor contouring method, and the ratio (expressed in percentage) of the overestimated areas of a gross tumor area (GTA_OE)/whole tumor areas on the macroscopic histology (WTA_H), which represented how much a particular GTA extended into the normal structures surrounding the primary tumor target, were calculated.

Results

The receiver operating characteristic curves of all pairs of FDG-PET images have a mean area under the curve value of 0.934 (CI of 0.911–0.954), for representing how well each contouring method accurately delineated the viable tumor area. FDG-PET single value threshold tumor contouring based on 30 and 35 % of tumor C_max or C_peak and 6 × C_liver + 2 × SD achieved a sensitivity greater than 90 % with a GTA_OE/WTA_H ratio less than 10 %. Contouring based on 50 % of C_max or C_peak had a much lower sensitivity of 67.2–75.6 % with a GTA_OE/WTA_H ratio of 1.1–1.7 %. Automated edge detection was not reliable in this system.

Conclusions

Single-value-threshold tumor contouring using ¹⁸F-FDG-PET is able to accurately delineate the viable portion of a tumor. 30 and 35 % of C_max, 30 and 35 % of C_peak, and 6 × C_liver + 2 × SD are three appropriate threshold values to delineate viable tumor volume in our animal model. The commonly used threshold value of 50 % of C_max or C_peak failed to detect one third of the viable tumor volume in our model.