Development and evaluation of albumin binder-conjugated heterodimeric radiopharmaceuticals targeting integrin αvβ3 and CD13 for cancer therapy

PURPOSE

The advancement of heterodimeric tracers, renowned for their high sensitivity, marks a significant trend in the development of radiotracers for cancer diagnosis. Our prior work on [68Ga]Ga-HX01, a heterodimeric tracer targeting CD13 and integrin αvβ3, led to its approval for phase I clinical trials by the China National Medical Production Administration (NMPA). However, its fast clearance and limited tumor retention pose challenges for broader clinical application in cancer treatment. This study aims to develop a new radiopharmaceutical with increased tumor uptake and prolonged retention, rendering it a potential therapeutic candidate.

METHODS

New albumin binder-conjugated compounds were synthesized based on the structure of HX01. In vitro and in vivo evaluation of these new compounds were performed after labelling with 68Ga. Small-animal PET/CT imaging were conducted at different time points at 0.5-6 h post injection (p.i.) using BxPC-3 xenograft mice models. The one with the best imaging performance was further radiolabeled with 177Lu for small-animal SPECT/CT and ex vivo biodistribution investigation.

RESULTS

We have synthesized novel albumin binder-conjugated compounds, building upon the structure of HX01. When radiolabeled with 68Ga, all compounds demonstrated improved pharmacokinetics (PK). Small-animal PET/CT studies revealed that these new albumin binder-conjugated compounds, particularly [68Ga]Ga-L6, exhibited significantly enhanced tumor accumulation and retention compared with [68Ga]Ga-L0 without an albumin binder. [68Ga]Ga-L6 outperformed [68Ga]Ga-L7, a compound developed using a previously reported albumin binder. Furthermore, [177Lu]Lu-L6 demonstrated rapid clearance from normal tissues, high tumor uptake, and prolonged retention in small-animal SPECT/CT and biodistribution studies, positioning it as an ideal candidate for radiotherapeutic applications.

CONCLUSION

A new integrin αvβ3 and CD13 targeting compound was screened out. This compound bears a novel albumin binder and exhibits increased tumor uptake and prolonged tumor retention in BxPC-3 tumors and low background in normal organs, making it a perfect candidate for radiotherapy when radiolabeled with 177Lu.

18F-Radiolabeling and Evaluation of an AMD3465 Derivative for PET Imaging of CXCR4 in a Mouse Breast Tumor Model

The exploration of pharmaceutically active agents and positron emission tomography (PET) tracers targeting CXCR4 has been a focal point in cancer research given its pivotal role in the development and progression of various cancers. While significant strides have been made in PET imaging with radiometal-labeled tracers, the landscape of 18F-labeled small molecule tracers remains relatively limited. Herein, we introduce a novel and promising derivative, [18F]SFB-AMD3465, as a targeted PET tracer for CXCR4. The compound was synthesized by modifying the pyridine ring of AMD3465, which was subsequently labeled with 18F using [18F]SFB. The study provides comprehensive insights into the design, synthesis, and biological evaluation of [18F]SFB-AMD3465. In vitro and in vivo assessments demonstrated the CXCR4-dependent, specific, and sensitive uptake of [18F]SFB-AMD3465 in the CXCR4-overexpressing 4T1 cell line and the corresponding xenograft-bearing mouse model. These findings contribute to bridging the gap in 18F-labeled PET tracers for CXCR4 and underscore the potential of [18F]SFB-AMD3465 as a PET radiotracer for in vivo CXCR4 imaging.

AI's deep dive into complex pediatric inguinal hernia issues: a challenge to traditional guidelines?

OBJECTIVE

This study utilized ChatGPT, an artificial intelligence program based on large language models, to explore controversial issues in pediatric inguinal hernia surgery and compare its responses with the guidelines of the European Association of Pediatric Surgeons (EUPSA).

METHODS

Six contentious issues raised by EUPSA were submitted to ChatGPT 4.0 for analysis, for which two independent responses were generated for each issue. These generated answers were subsequently compared with systematic reviews and guidelines. To ensure content accuracy and reliability, a content analysis was conducted, and expert evaluations were solicited for validation. Content analysis evaluated the consistency or discrepancy between ChatGPT 4.0's responses and the guidelines. An expert scoring method assess the quality, reliability, and applicability of responses. The TF-IDF model tested the stability and consistency of the two responses.

RESULTS

The responses generated by ChatGPT 4.0 were mostly consistent with the guidelines. However, some differences and contradictions were noted. The average quality score was 3.33, reliability score was 2.75, and applicability score was 3.46 (out of 5). The average similarity between the two responses was 0.72 (out of 1), Content analysis and expert ratings yielded consistent conclusions, enhancing the credibility of our research.

CONCLUSION

ChatGPT can provide valuable responses to clinical questions, but it has limitations and requires further improvement. It is recommended to combine ChatGPT with other reliable data sources to improve clinical practice and decision-making.

Preclinical evaluation of a dual-receptor targeted tracer [68Ga]Ga-HX01 in 10 different subcutaneous and orthotopic tumor models

PURPOSE

The integrin αvβ3 and aminopeptidase N (APN/CD13) play vital roles in the tumor angiogenesis process. They are highly expressed in a variety of tumor cells and proliferating endothelial cells during angiogenesis, which have been considered as highly promising targets for tumor imaging. Arginine-glycine-aspartic (RGD) and asparagine-glycine-arginine (NGR) are two peptides specifically binding to the integrin αvβ3 and CD13, respectively. In this study, we optimized our previously developed probe and preclinically evaluated the new integrin αvβ3 and CD13 dual-targeted probe, NOTA-RGD-NGR (denoted as HX01) radiolabeled with 68Ga, in 10 different subcutaneous and orthotopic tumor models.

METHODS

The specific activity and radiochemical purity of [68Ga]Ga-HX01 were identified. The dual-receptor targeting ability was confirmed by a series of blocking studies and partly muted tracers using BxPC-3 xenograft model. The dynamic imaging study and dose escalation study were explored to determine the optimal imaging time point and dosage in the BxPC-3 xenograft model. Next, we established a variety of subcutaneous and orthotopic tumor models including pancreas (BxPC-3), breast (MCF-7), gallbladder (NOZ), lung (HCC827), ovary (SK-OV-3), colorectal (HCT-8), liver (HuH-7), stomach (NUGC-4), and glioma (U87) cancers. All models underwent [68Ga]Ga-HX01 PET/CT imaging about 2 weeks post-inoculation, with a subset of them undergoing [18F]FDG PET/CT scan performed concurrently, and their results were compared. In addition, ex vivo biodistribution studies were also performed for verifying the semi-quantitative results of the non-invasive PET images.

RESULTS

[68Ga]Ga-HX01 significantly outperformed single target probes in the BxPC-3 xenograft model. All blocking and single target groups exhibited significantly descending tumor uptake. The high tumor uptakes were found in BxPC-3, MCF-7, and NOZ subcutaneous tumors (%ID/g > 1.1), while middle uptakes were observed in HCC827, SK-OV-3, HCT-8, and HuH-7 subcutaneous tumor (%ID/g 0.7-1.0). Due to the low background, the tumor-to-muscle and tumor-to-blood ratios of [68Ga]Ga-HX01 were higher than that of [18F]FDG.

CONCLUSIONS

[68Ga]Ga-HX01, as a dual target imaging agent, exhibited superior in vivo performance in different subcutaneous and orthotopic mice models of human tumors over [18F]FDG and its respectively mono-receptor targeted agents, which warrants the future clinical translation for tumor imaging.

[A semi-supervised network-based tissue-aware contrast enhancement method for CT images]

OBJECTIVE

To propose a tissue- aware contrast enhancement network (T- ACEnet) for CT image enhancement and validate its accuracy in CT image organ segmentation tasks.

METHODS

The original CT images were mapped to generate low dynamic grayscale images with lung and soft tissue window contrasts, and the supervised sub-network learned to recognize the optimal window width and level setting of the lung and abdominal soft tissues via the lung mask. The self-supervised sub-network then used the extreme value suppression loss function to preserve more organ edge structure information. The images generated by the T-ACEnet were fed into the segmentation network to segment multiple abdominal organs.

RESULTS

The images obtained by T-ACEnet were capable of providing more window setting information in a single image, which allowed the physicians to conduct preliminary screening of the lesions. Compared with the suboptimal methods, T-ACE images achieved improvements by 0.51, 0.26, 0.10, and 14.14 in SSIM, QABF, VIFF, and PSNR metrics, respectively, with a reduced MSE by an order of magnitude. When T-ACE images were used as input for segmentation networks, the organ segmentation accuracy could be effectively improved without changing the model as compared with the original CT images. All the 5 segmentation quantitative indices were improved, with the maximum improvement of 4.16%.

CONCLUSION

The T-ACEnet can perceptually improve the contrast of organ tissues and provide more comprehensive and continuous diagnostic information, and the T-ACE images generated using this method can significantly improve the performance of organ segmentation tasks.

[A semi-supervised material quantitative intelligent imaging algorithm for spectral CT based on prior information perception learning]

OBJECTIVE

To propose a semi-supervised material quantitative intelligent imaging algorithm based on prior information perception learning (SLMD-Net) to improve the quality and precision of spectral CT imaging.

METHODS

The algorithm includes a supervised and a self- supervised submodule. In the supervised submodule, the mapping relationship between low and high signal-to-noise ratio (SNR) data was constructed through mean square error loss function learning based on a small labeled dataset. In the self- supervised sub-module, an image recovery model was utilized to construct the loss function incorporating the prior information from a large unlabeled low SNR basic material image dataset, and the total variation (TV) model was used to to characterize the prior information of the images. The two submodules were combined to form the SLMD-Net method, and pre-clinical simulation data were used to validate the feasibility and effectiveness of the algorithm.

RESULTS

Compared with the traditional model-driven quantitative imaging methods (FBP-DI, PWLS-PCG, and E3DTV), data-driven supervised-learning-based quantitative imaging methods (SUMD-Net and BFCNN), a material quantitative imaging method based on unsupervised learning (UNTV-Net) and semi-supervised learning-based cycle consistent generative adversarial network (Semi-CycleGAN), the proposed SLMD-Net method had better performance in both visual and quantitative assessments. For quantitative imaging of water and bone materials, the SLMD-Net method had the highest PSNR index (31.82 and 29.06), the highest FSIM index (0.95 and 0.90), and the lowest RMSE index (0.03 and 0.02), respectively) and achieved significantly higher image quality scores than the other 7 material decomposition methods (P < 0.05). The material quantitative imaging performance of SLMD-Net was close to that of the supervised network SUMD-Net trained with labeled data with a doubled size.

CONCLUSIONS

A small labeled dataset and a large unlabeled low SNR material image dataset can be fully used to suppress noise amplification and artifacts in basic material decomposition in spectral CT and reduce the dependence on labeled data-driven network, which considers more realistic scenario in clinics.

Prediction of knee pain improvement over two years for knee osteoarthritis using a dynamic nomogram based on MRI-derived radiomics: a proof-of-concept study

OBJECTIVES

To develop and validate a nomogram to detect improved knee pain in osteoarthritis (OA) by integrating magnetic resonance imaging (MRI) radiomics signature of subchondral bone and clinical characteristics.

METHODS

Participants were selected from the Vitamin D Effects on Osteoarthritis (VIDEO) study. The primary outcome was 20% improvement of knee pain score over 2 years in participants administrated either vitamin D or placebo. Radiomics features of subchondral bone and clinical characteristics from 216 participants were extracted and analyzed. The participants were randomly split into the training and validation cohorts at a ratio of 8:2. Least absolute shrinkage and selection operator (LASSO) regression was used to select features and generate radiomics signatures. The optimal radiomics signature and clinical indicators were fitted into a nomogram using multivariable logistic regression model.

RESULTS

The nomogram showed favorable discrimination performance [AUC_training, 0.79 (95% CI: 0.72-0.79), AUC_validation, 0.83 (95% CI: 0.70-0.96)] as well as a good calibration. Additional contributing value of fusion radiomics signature to the nomogram was statistically significant (NRI, 0.23; IDI, 0.14, P < 0.001 in training cohort and NRI, 0.29; IDI, 0.18, P < 0.05 in validating cohort). Decision curve analysis confirmed the clinical usefulness of nomogram.

CONCLUSION

The radiomics-based nomogram comprising the MR radiomics signature and clinical variables achieves a favorable predictive efficacy and accuracy in differentiating improvement in knee pain among OA patients. This proof-of-concept study provides a promising way to predict clinically meaningful outcomes.

[Association analysis between genetic variants of matrix metalloproteinase enzyme 2 gene and the blood pressure of children and adolescents]

Objective: To explore the association between genetic variants of matrix metalloproteinase enzyme 2 (MMP2) gene and the blood pressure of children and adolescents. Methods: This cross-sectional study was performed in 2016 and included 4 155 children and adolescents in the urban area of Guangzhou. Physical examinations (including body height, weight, and blood pressure), questionnaires (including general characteristics, physical exercise, parental educational level, household income, etc.), and blood sampling were performed. Multivariable linear regression models were used to investigate the associations of MMP2 genetic variations (rs243865, rs7201) and the genetic risk score (GRS) level with standardized blood pressure. Mediating effect of standardized body mass index (BMI) was further assessed by process analysis in the association between GRS level and blood pressure, and potential additive interaction between physical activity and GRS level was analyzed using the product term in the regression model. Results: A total of 4 155 primary and secondary schoolchildren were finally included in the analysis, consisting of 1 401 (33.7%) second grade pupils of primary school, 1 422 (34.2%) first grade pupils of middle school, and 1 332 (32.1%) first-grade students of senior high school. After adjusting for age, sex, parental educational level, and family income, as compared to the rs243865 TT genotype, the CC/CT genotype increased diastolic blood pressure (DBP) by 0.461 standard deviations (SD) (β for dominant model=0.461, 95%CI 0.199-0.723). When compared to the rs7201 CC genotype, the AA/AC genotype showed 0.147 SD higher systolic blood pressure (SBP) (β for recessive model=0.147, 95%CI 0.014-0.279) and 0.171 SD increased DBP (β for recessive model=0.171, 95%CI 0.039-0.304). For each increment of GRS level, SBP and DBP increased by 0.151 SD (β for dominant model=0.151, 95%CI 0.029-0.272) and 0.242 SD (β=0.242, 95%CI 0.120-0.363), respectively. The mediating effect of BMI accounted for 28.3% and 12.6% of the total effect of GRS on SBP and DBP, respectively. After controlling BMI, the direct effect of GRS on DBP remained statistically significant (P<0.001). The insufficient moderate-to-vigorous physical activity (<0.5 h/d) showed a significant interaction with GRS on SBP under additive scale (β for interaction=0.518, 95%CI 0.088-0.949, P=0.018). Conclusions: rs243865 and rs7201 variants in MMP2 gene are associated with the elevated blood pressure of children and adolescents. Obesity may yield a mediation role in the associations, while insufficient physical activity may have a positively additive interaction with MMP2 genetic variants.

Heterodimeric RGD-NGR PET Tracer for the Early Detection of Pancreatic Cancer

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal gastrointestinal cancer, and its poor prognosis is highly associated with the lack of an efficient early detection technology. Here, we report that RGD-NGR heterodimer labeled with PET isotope could be applied in PDAC early detection.

PROCEDURES

The RGD-NGR tracer was first compared with its corresponding monomeric counterparts via PET imaging studies using mice bearing a subcutaneous BxPC3 tumor. Subsequently, the RGD-NGR tracer was evaluated in autochthonous mouse models with spontaneously developed late stage PanIN lesions (KCER mice) or PDAC (KPC mice) via both PET imaging studies and ex vivo biodistribution studies. Furthermore, a comparison between 2-deoxy-2[18F]fluoro-D-glucose ([18F]F-FDG) and the RGD-NGR tracer was conducted via PET imaging of the same KCH mouse bearing spontaneously developed PDAC. H&E staining was performed to confirm the malignant pancreatic tissue in the KCH mouse. Immunofluorescence staining was performed to confirm the expression of integrin αVβ3 and CD13.

RESULTS

The RGD-NGR tracer exhibited improved in vivo performance as compared with its corresponding monomeric counterparts on the subcutaneous BxPC3 tumor mouse model. Subsequent evaluation in autochthonous mouse models demonstrated its capability to detect both pre-malignant and malignant pancreases. Further comparison with [18F]F-FDG revealed the superiority of the proposed heterodimer in imaging spontaneously developed PDAC. H&E staining confirmed the malignant pancreatic tissue in the KCH mouse, while the expression of both integrin αVβ3 and CD13 receptors was demonstrated with immunofluorescence staining.

CONCLUSION

The proposed RGD-NGR heterodimer possesses the potential to be applied in the PDAC early detection for high-risk populations.

Evaluation of a CD13 and Integrin αvβ3 Dual-Receptor Targeted Tracer 68Ga-NGR-RGD for Ovarian Tumor Imaging: Comparison With 18F-FDG

Ovarian cancer has the highest mortality rate of gynecologic malignancy. ¹⁸F-FDG positron emission tomography (PET) adds an important superiority over traditional anatomic imaging modalities in oncological imaging but has drawbacks including false negative results at the early stage of ovarian cancer, and false positives when inflammatory comorbidities are present. Aminopeptidase N (APN, also known as CD13) and integrin α_vβ₃ are two important targets overexpressed on tumor neo-vessels and frequently on ovarian cancerous cells. In this study, we used subcutaneous and metastatic models of ovarian cancer and muscular inflammation models to identify ⁶⁸Ga-NGR-RGD, a heterodimeric tracer consisting of NGR and RGD peptides targeting CD13 and integrin α_vβ₃, respectively, and compared it with ¹⁸F-FDG. We found that ⁶⁸Ga-NGR-RGD showed greater contrast in SKOV3 and ES-2 tumors than ¹⁸F-FDG. Low accumulation of ⁶⁸Ga-NGR-RGD but avid uptake of ¹⁸F-FDG were observed in inflammatory muscle. In abdominal metastasis models, PET imaging with ⁶⁸Ga-NGR-RGD allowed for rapid and clear delineation of both peritoneal and liver metastases (3-6 mm), whereas, ¹⁸F-FDG could not distinguish the metastasis lesions due to the relatively low metabolic activity in tumors and the interference of intestinal physiological ¹⁸F-FDG uptake. Due to the high tumor-targeting efficacy, low inflammatory uptake, and higher tumor-to-background ratios compared to that of ¹⁸F-FDG, ⁶⁸Ga-NGR-RGD presents a promising imaging agent for diagnosis, staging, and follow-up of ovarian tumors.

Development of Dual Receptor Enhanced Pre-Targeting Strategy-A Novel Promising Technology for Immuno-Positron Emission Tomography Imaging

PET imaging has become an important diagnostic tool in the era of precise medicine. Various pre-targeting systems have been reported to address limitations associated with traditional immuno-PET. However, the application of these mono-receptor based pre-targeting (MRPT) strategies is limited to non-internalizable antibodies, and the tumor uptake is usually much lower than that in the corresponding immuno-PET. To circumvent these limitations, we develop the first Dual-Receptor Pre-Targeting (DRPT) system through entrapping the tumor-receptor-specific radioligand by the pre-administered antibody. Besides the similar ligation pathway happens in MRPT, incorporation of a tumor-receptor-specific peptide into the radioligand in DRPT enhances both concentration and retention of the radioligand on tumor, promoting its ligation with pre-administered mAb on cell-surface and/or internalized into tumor-cells. In this study, 64Cu based DRPT shows superior performance over corresponding MRPT and immuno-PET using internalizable antibodies. Besides, the compatibility of DRPT with short-lived and generator-produced 68Ga is demonstrated, leveraging its advantage in reducing radio-dose exposure. Furthermore, the feasibility of reducing the amount of the pre-administered antibody is confirmed, indicating the cost saving potential of DRPT. In summary, synergizing advantages of dual-receptor targeting and pre-targeting, we expect that this DRPT strategy can become a breakthrough technology in the field of antibody-based molecular imaging.

[Time-series analysis on the relationship between ambient PM2.5 and daily outpatient visits due to allergic conjunctivitis among children in Shenzhen]

Objective: To explore the short-term effects of ambient PM_2.5 on the outpatient visits of allergic conjunctivitis among children in Shenzhen. Methods: It was a ecological study. Data on daily visits including date of visit, sex and age from children with allergic conjunctivitis were collected from Shenzhen Eye Hospital and Shenzhen Children's Hospital in 2018. Related data on air pollution (PM_2.5, PM₁₀, SO₂, NO₂, CO and O₃) and meteorology (atmospheric pressure, temperature and relative humidity) were also collected. Pearson correlation analysis was used for normal distribution data and Spearman rank correlation analysis was used for non-normal distribution data. Generalized additive model was used to estimate the impact of PM_2.5 pollution on allergic conjunctivitis outpatients and the lagging effects. Results: In 2018, there were 16 133 allergic conjunctivitis outpatients in the two hospitals. The maximum age was 18 years and the minimum age was 2 months. Males accounted for 49.3%. The daily average concentration of PM_2.5 was 22 (15, 31) μg/m³. Changes of the concentration of PM_2.5 had a positive correlation with the amount of allergic conjunctivitis visits, and the Spearman correlation coefficient was 0.150 (P=0.004). The single pollutant model showed that the strongest effect appeared at 3 days (RR=1.111， 95%CI:1.071-1.152). A 10 μg/m³ increase of PM_2.5 would result in an excessive number of allergic conjunctivitis outpatients as much as 11.112% (95%CI：7.011%-15.212%). In the multiple air pollutants models, after the introduction of NO₂, O₃ and CO, the concentration of PM_2.5 showed an enhanced effect on the number of hospital visits due to allergic conjunctivitis on the same day, and the difference was statistically significant (P<0.05). Conclusion: Changes of the concentration of PM_{2.5 h}ad a positive correlation with daily outpatient visits of allergic conjunctivitis among children in Shenzhen. (Chin J Ophthalmol, 2020, 56: 608-614).

MicroRNA-374b accelerates the development of lung cancer through downregulating PTEN expression via activating PI3K/Akt pathway

OBJECTIVE

To elucidate whether microRNA-374b could participate in the development of lung cancer (LC) through downregulating PTEN (gene of phosphate and tensin homolog deleted on chromosome ten) expression via activating PI3K/Akt pathway.

PATIENTS AND METHODS

Expression levels of microRNA-374b and PTEN in LC tissues and adjacent normal tissues were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Moreover, the expression level of microRNA-374b in LC cell lines was detected as well. The microRNA-374b inhibitor was constructed and transfected to downregulate microRNA-374b expression in A549 and H358 cells. The regulatory effects of microRNA-374b on migratory and proliferative capacities of LC cells were explored by wound healing and cell counting kit-8 (CCK-8) assay, respectively. After co-transfection of microRNA-374b inhibitor and si-PTEN in LC cells, expression levels of PTEN/PI3K/Akt were determined by qRT-PCR and Western blot.

RESULTS

QRT-PCR results showed that microRNA-374b expression was higher, while PTEN expression was lower in LC tissues than adjacent tissues. Identically, microRNA-374b was also highly expressed in LC cell lines. PTEN expression was negatively correlated with microRNA-374b expression in LC. The downregulation of microRNA-374b in A549 and H358 cells inhibited their migratory and proliferative potentials. Subsequently, we verified that microRNA-374b could bind to PTEN through dual-luciferase reporter gene assay. MicroRNA-374b could inhibit PTEN expression and activate the PI3K/Akt pathway. Furthermore, PTEN knockdown enhanced migratory and proliferative abilities of LC cells, which were attenuated by co-transfection of microRNA-374b inhibitor.

CONCLUSIONS

MicroRNA-374b promotes the development of LC by downregulating PTEN expression through activating PI3K/Akt pathway.

1144 Actigraphy-defined Sleep And Neurocognitive Decline In Middle-age Hispanic/Latino Adults

Introduction

Few studies have evaluated objective sleep measures and longitudinal neurocognitive decline, particularly in middle-age or Hispanic/Latino adults. We evaluated prospective associations between actigraphy-defined sleep and 7-year neurocognitive change among Hispanic/Latino adults. We hypothesized that sleep duration would be associated with neurocognitive decline.

Methods

We analyzed data from 1,036 adults 45-64 years of age from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL), a multi-center prospective cohort study of diverse community-dwelling Hispanic/Latino adults. At Visit 1 (2008-2011), participants underwent neurocognitive assessments, 7-days of actigraphy, home sleep testing, and sleep questionnaires (including the Insomnia Severity Index). Seven years later, participants repeated neurocognitive assessments. The neurocognitive battery included the Six-Item Screener, Brief Spanish-English Verbal Learning Test, phonemic word fluency test, and Digit Symbol Subtest. Survey linear regression was used to evaluate prospective associations between actigraphy-defined or self-reported sleep variables and neurocognitive change. Final models adjusted for objectively-defined variables (age, body-mass index, Field Center, and time between neurocognitive assessments), and self-reported variables (sex, education, Hispanic/Latino background, alcohol consumption, physical activity, heart failure, cerebrovascular events, depression and anxiety symptoms, and antidepressant use).

Results

At Visit 1, the sample was 55% female and mean age was 54.9±2.2 years. The mean sleep duration was 402.6±27.6 minutes, mean sleep-onset latency was 11.3±9.7 minutes, mean number of days with naps of ≥ 15 minutes duration was 1.1±0.7, and mean sleep-time per nap was 51±14.1 minutes. Increased sleep-onset latency was associated with 7-year declines in global neurocognitive function (β=-0.0026, p&lt;0.01), verbal learning (β=-0.0028, p&lt;0.001) and verbal memory (β=-0.036, p&lt;0.05). Increased sleep-time per nap predicted better verbal memory (β=0.0038, p&lt;0.05). In contrast, sleep duration, sleep fragmentation, and self-reported sleep measures were not associated with neurocognitive change.

Conclusion

Among middle-age adults, sleep-onset latency and nap duration were associated with neurocognitive change. These findings may serve as targets for intervention of neurocognitive decline.

Support

This work is supported by the National Institute on Aging: R01AG048642, RF1AG054548, R01AG061022, R21AG056952, and R21HL140437 (AR).

Photo-Click-Facilitated Screening Platform for the Development of Hetero-Bivalent Agents with High Potency

A novel photo-click-based platform has been developed for rapid screening and affinity optimization of heterobivalent agents. This method allows for the efficient selection of high-affinity dual receptor-targeting agents via streamlining tedious organic synthesis and biological evaluation procedures required by traditional approaches. The high-avidity heterobivalent agents targeting both integrin α_vβ₃ and urokinase-type plasminogen activator receptors have been developed using this photo-click-facilitated screening platform. The affinity screening results were further validated by traditional in vitro and in vivo evaluation techniques, reaffirming the reliability of the method. The convenience, rapidity, universality, and robustness of the screening platform, discussed in this report, can greatly facilitate the development of new heterobivalent agents for research and/or clinical applications.

Thermally sensitive fluorescence imaging system for radiofrequency ablation guidance

Radiofrequency ablation (RFA) has been clinically used as a minimally invasive procedure for the treatment of many solid tumors. However, the current imaging techniques have some shortages in RFA guidance, especially for the assessment of the margin of ablation. Herein, we developed a novel optical imaging platform to guide RFA utilizing fluorescence resonance energy transfer from a thermally sensitive fluorescent protein conjugated to a near-infrared fluorescent dye. Additionally, attaching receptor-targeting ligands further equipped the system with high specificity to tumors overexpressing the targeted receptor.

Comparison of Al18F- and 68Ga-labeled NOTA-PEG4-LLP2A for PET imaging of very late antigen-4 in melanoma

Malignant melanoma is an aggressive cancer with poor prognosis. Very late antigen-4 (VLA-4) is overexpressed in melanoma and many other tumors, making it an attractive target for developing molecular diagnostic and therapeutic agents. We compared Al18F- and 68Ga-labeled LLP2A peptides for PET imaging of VLA-4 expression in melanoma. The peptidomimetic ligand LLP2A was modified with chelator 2-S-(4-isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid (p-SCN-Bn-NOTA), and the resulting NOTA-PEG4-LLP2A peptide was then radiolabeled with Al18F or 68Ga. The two labeled peptides were assayed for in vitro and in vivo VLA-4 targeting efficiency. Good Al18F and 68Ga radiolabeling yields were achieved, and the resulting PET tracers showed good serum stability. In the in vivo evaluation of the B16F10 xenograft mouse model, both tracers exhibited high accumulation with good contrast in static PET images. Compared with 68Ga-NOTA-PEG4-LLP2A, Al18F-NOTA-PEG4-LLP2A resulted in relatively higher background, including higher liver uptake (1 h: 20.1 ± 2.6 vs. 15.3 ± 1.7%ID/g, P < 0.05; 2 h: 11.0 ± 1.2 vs. 8.0 ± 0.8%ID/g, P < 0.05) and lower tumor-to-blood ratios (2.5 ± 0.4 vs. 3.3 ± 0.5 at 1 h, P < 0.05; 5.1 ± 0.9 vs. 7.3 ± 0.6 at 2 h, P < 0.01) at some time points. The results obtained from the mice blocked with unlabeled peptides and VLA-4-negative A375 xenografts groups confirmed the high specificity of the developed tracers. Despite the relatively high liver uptake, both Al18F-NOTA-PEG4-LLP2A and 68Ga-NOTA-PEG4-LLP2A exhibited high VLA-4 targeting efficacy with comparable in vivo performance, rendering them promising candidates for imaging tumors that overexpress VLA-4.

Evaluation of an Integrin αvβ3 and Aminopeptidase N Dual-Receptor Targeting Tracer for Breast Cancer Imaging

Integrin αvβ3 and aminopeptidase N (APN, also known as CD13) are two important targets involved in the regulation of angiogenesis, tumor proliferation, invasion, and metastasis. In this study, we developed a heterodimeric tracer consisting of arginine-glycine-aspartic (RGD) and asparagine-glycine-arginine (NGR) peptides targeting αvβ3 and CD13, respectively, for PET imaging of breast cancer. The NGR peptide was first modified with N3-NOtB2 and then conjugated to BCN-PEG4-c(RGDyK) via copper-free click chemistry. The resulting precursor was purified and radiolabeled with gallium-68. Small-animal PET/CT imaging and post-imaging biodistribution studies were performed in mice bearing human breast cancer MCF-7, MDA-MB-231, MDA-MB-468, and MX-1 xenografts and pulmonary metastases models. The expression levels of αvβ3 and CD13 in tumors were checked via immunochemical staining. The heterodimeric tracer was successfully synthesized and radiolabeled with gallium-68 at a molar activity of 45-100 MBq/nmol at the end of synthesis. It demonstrated high in vitro and in vivo stability. In static PET/CT imaging studies, the MCF-7 tumor could be clearly visualized and exhibited higher uptake at 30 min post injection of 68Ga-NGR-RGD than that of either 68Ga-RGD or 68Ga-NGR alone. High specificity was shown in blocking studies using Arg-Gly-Asp (RGD) and Asp-Gly-Arg (NGR) peptides. The MCF-7 tumor exhibited the highest uptake of 68Ga-NGR-RGD followed by MDA-MB-231, MDA-MB-468, and MX-1 tumors. This was consistent with their expression levels of CD13 and αvβ3 as confirmed by western blot and immunohistochemical staining. Metastatic lesions in the lungs were clearly detectable on 68Ga-NGR-RGD PET/CT imaging in mouse models of pulmonary metastases. 68Ga-NGR-RGD, a CD13 and αvβ3 dual-receptor targeting tracer, showed higher binding avidities, targeting efficiency, and longer tumor retention time compared with monomeric 68Ga-NGR and 68Ga-RGD. Its promising in vivo performance makes it an ideal candidate for future clinical translation.

Over-expression of both VEGF-C and Twist predicts poor prognosis in human breast cancer

BACKGROUND

Angiogenesis is an indispensable step in the growth and invasiveness of breast cancers involving a series of exquisite molecular steps. Pro-angiogenic factors, including vascular endothelial growth factor (VEGF), have been recognized as pivotal therapeutic targets in the treatment of breast cancer. More recently, a highly conserved transcription factor Twist has been reported to be involved in tumor angiogenesis and metastasis.

METHODS

The expression of VEGF-C and Twist was immunohistochemically determined in tissue samples of primary tumors from 408 patients undergoing curative surgical resection for breast cancer. The correlations of VEGF-C and Twist expressions with clinicopathologic parameters as well as survival outcomes were evaluated.

RESULTS

Of the 408 patients evaluated, approximately 70% had high expression of VEGF-C which was significantly associated with advanced tumor stages (P = 0.019). Similarly, VEGF-C expression was associated with the proliferation index Ki67, N3 lymph node metastasis, and D2-40-positive lymphatic vessel invasion (LVI) in a univariate analysis. Furthermore, patients with high expressions of VEGF-C and Twist (V + T+) had significantly increased lymph node metastasis, higher clinical stage, and worse disease-free survival, DFS (P = 0.001) and overall survival, OS (P = 0.011).

CONCLUSIONS

Our results suggested that co-expression of VEGF-C and Twist was associated with larger tumor size, higher numbers of lymph node involvement, D2-40-positive LVI, higher risk of distant metastasis, and worse DFS or OS in breast cancer patients.

64Cu-Labeled Ubiquitin for PET Imaging of CXCR4 Expression in Mouse Breast Tumor

Ubiquitin has been recently identified as a chemokine receptor 4 (CXCR4) natural ligand, offering great potential for positron emission computed tomography (PET) imaging of CXCR4 expression. This study reports the preparation and evaluation of (64Cu)-radiolabeled ubiquitin for CXCR4 imaging. The ubiquitin was first fused with a C-terminal GGCGG sequence, and the resulting recombinant ubiquitin derivative UbCG4 was then functionalized with the trans-cyclooctene (TCO) moiety via thiol-maleimide click reaction, followed by 64Cu-radiolabeling through the TCO/Tz (tetrazine)-based Diels-Alder click reaction. In the prepared in vitro studies, the prepared (64Cu)-UbCG4 showed significantly higher specific uptakes in the 4T1 breast cancer cells compared with the uptakes in the CXCR4-knockdown 4T1 cells. In the in vivo evaluation in the 4T1-xenograft mouse model, (64Cu)-UbCG4 demonstrated a similar tumor uptake but much lower backgrounds compared with 64Cu-labeled AMD3465. These results suggested that (64Cu)-UbCG4 could serve as a potent PET tracer for the noninvasive imaging of CXCR4 expression in tumors.

Assessment of delayed graft function using susceptibility-weighted imaging in the early period after kidney transplantation: a feasibility study

PURPOSE

This study aimed to explore the feasibility of susceptibility-weighted imaging (SWI) for evaluating delayed graft function (DGF) during the early posttransplantation period.

METHODS

Sixty-nine recipients who accepted allograft renal transplantation underwent SWI during the second posttransplantation week. Renal allograft function was estimated via the glomerular filtration rate. Recipients with and without DGF were identified. For each transplanted kidney, the presence of abnormal signal intensity lesions (ASILs), excluding benign lesions, on SWI was assessed. Renal allograft function was compared between the recipients with and without ASILs. The correlation between ASILs and renal allograft function was tested by Spearman's rank correlation analysis.

RESULTS

Thirty-four recipients were diagnosed with DGF, while 35 recipients showed no DGF. In the DGF group, 16 recipients had low-intensity ASILs, primarily at the corticomedullary junction of transplanted kidneys on SWI, and no ASILs were found in 18 recipients. In the non-DGF group, none of the recipients showed ASILs on SWI. In the DGF group, the renal allograft function among the 16 recipients with low-intensity ASILs was significantly lower than that among the other 18 recipients (8.5 ± 4.2 vs. 19.7 ± 9.7 mL/min, P < 0.001). The presence of low-intensity ASILs on SWI showed a moderate negative correlation with renal allograft function in recipients with DGF (r = - 0.553, P = 0.001).

CONCLUSION

SWI can be used to evaluate DGF in the early post-kidney transplantation period.

Synthesis and Evaluation of New Bifunctional Chelators with Phosphonic Acid Arms for Gallium-68 Based PET Imaging in Melanoma

Due to the increasing use of generator-produced radiometal Gallium-68 (⁶⁸Ga) in positron-emission tomography/computed tomography (PET/CT), reliable bifunctional chelators that can efficiently incorporate ⁶⁸Ga³⁺ into biomolecules are highly desirable. In this study, we synthesized two new bifunctional chelators bearing one or two phosphonic acid functional groups, named p-SCN-PhPr-NE2A1P and p-SCN-PhPr-NE2P1A, with the aim of enabling facile production of ⁶⁸Ga-based radiopharmaceuticals. Both chelators were successfully conjugated to LLP2A-PEG₄, a very late antigen-4 (VLA-4) targeting peptidomimetic ligand, to evaluate their application in ⁶⁸Ga-based PET imaging. NE2P1A-PEG₄-LLP2A exhibited the highest ⁶⁸Ga³⁺ binding ability with molar activity of 37 MBq/nmol under mild temperature and neutral pH. Excellent serum stability of ⁶⁸Ga-NE2P1A-PEG₄-LLP2A was observed, which was consistent with the result obtained from density functional theory calculation. The in vitro cell study showed that ⁶⁸Ga-NE2P1A-PEG₄-LLP2A had significantly longer retention in B16F10 cells comparing to the reported retention of ⁶⁴Cu-NE3TA-PEG₄-LLP2A, although the uptake was relatively lower. In the biodistribution and micro-PET/CT imaging studies, high tumor uptake and low background were observed after ⁶⁸Ga-NE2P1A-PEG₄-LLP2A was injected into mice bearing B16F10 tumor xenografts, making it a highly promising radiotracer for noninvasive imaging of VLA-4 receptors overexpressed in melanoma.

64Cu-Labeled Phosphonate Cross-Bridged Chelator Conjugates of c(RGDyK) for PET/CT Imaging of Osteolytic Bone Metastases

OBJECTIVE

The goal of this research was to evaluate c(RGDyK) conjugated to phosphonate-based cross-bridged chelators using Cu-free click chemistry in the 4T1 mouse mammary tumor bone metastasis model in comparison with ⁶⁴Cu-CB-TE2A-c(RGDyK), which previously showed selective binding to integrin αvβ3 on osteoclasts.

EXPERIMENTAL

Two phosphonate-based cross-bridged chelators (CB-TE1A1P and CB-TE1K1P) were conjugated to c(RGDyK) through bio-orthogonal strain-promoted alkyne-azide cycloaddition. In vitro and in vivo evaluation of the ⁶⁴Cu-labeled TE1A1P-DBCO-c(RGDyK) (AP-c(RGDyK)), TE1K1P-PEG4-DBCO-c(RGDyK) (KP-c(RGDyK)), and CB-TE2A-c(RGDyK) were compared in the 4T1 mouse model of bone metastasis. The affinities of the unconjugated and chelator-c(RGDyK) analogs for αvβ3 integrin were determined using a competitive-binding assay. For in vivo evaluation, BALB/c mice were injected with 1 × 10⁵ 4T1/Luc cells in the left ventricle. Formation of metastases was monitored by bioluminescence imaging (BLI) followed by small-animal PET/CT 2 h postinjection of radiotracers.

RESULTS

The chelator-peptide conjugates showed similar affinity to integrin αvβ3, in the low nM range. PET imaging demonstrated a higher uptake in bones having metastases for all ⁶⁴Cu-labeled c(RGDyK) analogs compared with bones in nontumor-bearing mice. The correlation between uptake of ⁶⁴Cu-AP-c(RGDyK) and ⁶⁴Cu-KP-c(RGDyK) in bones with metastases based on PET/CT imaging, and osteoclast number based on histomorphometry, was improved over the previously investigated ⁶⁴Cu-CB-TE2A-c(RGDyK).

CONCLUSION

These data suggest that the phosphonate chelator conjugates of c(RDGyK) peptides are promising PET tracers suitable for imaging tumor-associated osteoclasts in bone metastases.

A multi-functional polymeric carrier for simultaneous positron emission tomography imaging and combination therapy

Multifunctional nanoplatforms offering simultaneous imaging and therapeutic functions have been recognized as a highly promising strategy for personalized nanomedicine. In this work, we synthesized a farnesylthiosalicylate (FTS, a nontoxic Ras antagonist) based triblock copolymer POEG-b-PVBA-b-PFTS (POVF) composed of a poly(oligo(ethylene glycol) methacrylate) (POEG) hydrophilic block, a poly(FTS) hydrophobic block, and a poly(4-vinylbenzyl azide) (PVBA) middle block. The POVF polymer itself was active in inhibiting the tumor growth in vitro and in vivo. Besides, it could serve as a carrier to effectively encapsulate paclitaxel (PTX) to form stable PTX/POVF mixed micelles with a diameter around 100 nm. Meanwhile, POVF polymer provides the active azide group for incorporating a positron emission tomography (PET) imaging modality via a facile strategy based on metal-free click chemistry. This nanocarrier system could not only be used for co-delivery of PTX and FTS, but also for PET imaging guided drug delivery. In the 4T1.2 tumor bearing mice, PET imaging showed rapid uptake and slow clearance of radiolabeled PTX/POVF nanomicelles in the tumor tissues. In addition, the FTS-based multi-functional nanocarrier was able to inhibit tumor growth effectively, and the co-delivery of PTX by the carrier further improved the therapeutic effect.

STATEMENT OF SIGNIFICANCE

Due to the intrinsic heterogeneity of cancer and variability in individual patient response, personalized nanomedicine based on multi-functional carriers that integrate the functionalities of combination therapy and imaging guidance is highly demanded. Here we developed a multi-functional nanocarrier based on triblock copolymer POEG-b-PVBA-b-PFTS (POVF), which could not only be used for co-delivery of anticancer drugs PTX and Ras inhibitor FTS, but also for PET imaging guided drug delivery. The POVF carrier itself was active in inhibiting the tumor growth in vitro and in vivo. Besides, it was effective in formulating PTX with high drug loading capacity, which further enhanced the tumor inhibition effect. Meanwhile, we developed a simple and universal approach to incorporate a PET radioisotope (Zr-89 and Cu-64) into the azide-containing PTX/POVF micelles via metal-free click chemistry in aqueous solution. The radiolabeled PTX/POVF micelles exhibited excellent serum stability, rapid tumor uptake and slow clearance, which validated the feasibility of the PET image-guided delivery of PTX/POVF micelles.

Appropriate dose of Lactobacillus buchneri supplement improves intestinal microbiota and prevents diarrhoea in weaning Rex rabbits

This study examined the effects on intestinal microbiota and diarrhoea of Lactobacillus buchneri supplementation to the diet of weaning Rex rabbits. To this end, rabbits were treated with L. buchneri at two different doses (LC: 104 cfu/g diet and HC: 105 cfu/g diet) for 4 weeks. PCR-DGGE was used to determine the diversity of the intestinal microbiota, while real-time PCR permitted the detection of individual bacterial species. ELISA and real-time PCR allowed the identification of numerous cytokines in the intestinal tissues. Zonula occludens-1, polymeric immunoglobulin receptor and immunoglobulin A genes were examined to evaluate intestinal barriers. Results showed that the biodiversity of the intestinal microbiota of weaning Rex rabbits improved in the whole tract of the treated groups. The abundance of most detected bacterial species was highly increased in the duodenum, jejunum and ileum after L. buchneri administration. The species abundance in the HC group was more increased than in the LC group when compared to the control. Although the abundance of Enterobacteriaceae exhibited a different pattern, Escherichia coli was inhibited in all treatment groups. Toll-like receptor (TLR)2 and TLR4 genes were down-regulated in all intestinal tissues as the microbiota changed. In the LC group, the secretion of the inflammatory cytokine tumour necrosis factor-α was reduced, the gene expression of the anti-inflammatory cytokine interleukin (IL)-4 was up-regulated and the expression of intestinal-barrier-related genes was enhanced. Conversely, IL-4 expression was increased and the expression of other tested genes did not change in the HC group. The beneficial effects of LC were greater than those of HC or the control in terms of improving the daily weight gain and survival rate of weaning Rex rabbits and reducing their diarrhoea rate. Therefore, 104 cfu/g L. buchneri treatment improved the microbiota of weaning Rex rabbits and prevented diarrhoea in these animals.

Gene expression profiles for a prognostic immunoscore in gastric cancer

Background

Increasing evidence has indicated an association between immune infiltration in gastric cancer and clinical outcome. However, reliable prognostic signatures, based on systematic assessments of the immune landscape inferred from bulk tumour transcriptomes, have not been established. The aim was to develop an immune signature, based on the cellular composition of the immune infiltrate inferred from bulk tumour transcriptomes, to improve the prognostic predictions of gastric cancer.

Methods

Twenty‐two types of immune cell fraction were estimated based on large public gastric cancer cohorts from the Gene Expression Omnibus using CIBERSORT. An immunoscore based on the fraction of immune cell types was then constructed using a least absolute shrinkage and selection operator (LASSO) Cox regression model.

Results

Using the LASSO model, an immunoscore was established consisting of 11 types of immune cell fraction. In the training cohort (490 patients), significant differences were found between high‐ and low‐immunoscore groups in overall survival across and within subpopulations with an identical TNM stage. Multivariable analysis revealed that the immunoscore was an independent prognostic factor (hazard ratio 1·92, 95 per cent c.i. 1·54 to 2·40). The prognostic value of the immunoscore was also confirmed in the validation (210) and entire (700) cohorts.

Conclusion

The proposed immunoscore represents a promising signature for estimating overall survival in patients with gastric cancer.

Immunoscore predicts prognosis

JTC801 Induces pH-dependent Death Specifically in Cancer Cells and Slows Growth of Tumors in Mice

BACKGROUND & AIMS

Maintenance of acid-base homeostasis is required for normal physiology, metabolism, and development. It is not clear how cell death is activated in response to changes in pH. We performed a screen to identify agents that induce cell death in a pH-dependent manner (we call this alkaliptosis) in pancreatic ductal adenocarcinoma cancer (PDAC) cells and tested their effects in mice.

METHODS

We screened a library of 254 compounds that interact with G-protein-coupled receptors (GPCRs) to identify those with cytotoxic activity against a human PDAC cell line (PANC1). We evaluated the ability of JTC801, which binds the opiod receptor and has analgesic effects, to stimulate cell death in human PDAC cell lines (PANC1, MiaPaCa2, CFPAC1, PANC2.03, BxPc3, and CAPAN2), mouse pancreatic cancer-associated stellate cell lines, primary human pancreatic ductal epithelial cells, and 60 cancer cell lines (the NCI-60 panel). Genes encoding proteins in cell death and GPCR signaling pathways, as well as those that regulate nuclear factor-κB (NF-κB) activity, were knocked out, knocked down, or expressed from transgenes in cancer cell lines. JTC801 was administered by gavage to mice with xenograft tumors, C57BL/6 mice with orthographic pancreatic tumors grown from Pdx1-Cre;KRas^G12D/+;Tp53^R172H/+ (KPC) cells, mice with metastases following tail-vein injection of KPC cells, and Pdx-1-Cre;Kras^G12D/+ mice crossed with Hmgb1^flox/flox mice (KCH mice). Pancreata were collected from mice and analyzed for tumor growth and by histology and immunohistochemistry. We compared gene and protein expression levels between human pancreatic cancer tissues and patient survival times using online R2 genomic or immunohistochemistry analyses.

RESULTS

Exposure of human PDAC cell lines (PANC1 and MiaPaCa2) to JTC801 did not induce molecular markers of apoptosis (cleavage of caspase 3 or poly [ADP ribose] polymerase [PARP]), necroptosis (interaction between receptor-interacting serine-threonine kinase 3 [RIPK3] and mixed lineage kinase domain like pseudokinase [MLKL]), or ferroptosis (degradation of glutathione peroxidase 4 [GPX4]). Inhibitors of apoptosis (Z-VAD-FMK), necroptosis (necrosulfonamide), ferroptosis (ferrostatin-1), or autophagy (hydroxychloroquine) did not prevent JTC801-induced death of PANC1 or MiaPaCa2 cells. The cytotoxic effects of JTC801 in immortalized fibroblast cell lines was not affected by disruption of genes that promote apoptosis (Bax^-/-/Bak^-/- cells), necroptosis (Ripk1^-/-, Ripk3^-/-, or Mlkl^-/- cells), ferroptosis (Gpx4^-/- cells), or autophagy (Atg3^-/-, Atg5^-/-, Atg7^-/-, or Sqstm1^-/- cells). We found JTC801 to induce a pH-dependent form cell death (alkaliptosis) in cancer cells but not normal cells (hepatocytes, bone marrow CD34⁺ progenitor cells, peripheral blood mononuclear cells, or dermal fibroblasts) or healthy tissues of C57BL/6 mice. JTC801 induced alkaliptosis in cancer cells by activating NF-κB, which repressed expression of the carbonic anhydrase 9 gene (CA9), whose product regulates pH balance in cells. In analyses of Cancer Genome Atlas data and tissue microarrays, we associated increased tumor level of CA9 mRNA or protein with shorter survival times of patients with pancreatic, kidney, or lung cancers. Knockdown of CA9 reduced the protective effects of NF-κB inhibition on JTC801-induced cell death and intracellular alkalinization in PANC1 and MiaPaCa2 cell lines. Oral administration of JTC801 inhibited growth of xenograft tumors (from PANC1, MiaPaCa2, SK-MEL-28, PC-3, 786-0, SF-295, HCT116, OV-CAR3, and HuH7 cells), orthotropic tumors (from KPC cells), lung metastases (from KPC cells) of mice, and slowed growth of tumors in KCH mice.

CONCLUSIONS

In a screen of agents that interact with GPCR pathways, we found JTC801 to induce pH-dependent cell death (alkaliptosis) specifically in cancer cells such as PDAC cells, by reducing expression of CA9. Levels of CA9 are increased in human cancer tissues. JTC801 might be developed for treatment of pancreatic cancer.

Fat status detection and histotypes differentiation in solid renal masses using Dixon technique

PURPOSE

To detect fat status and differentiate histotypes of renal masses by using Dixon technique.

MATERIALS AND METHODS

This study included 134 solid renal masses. Signal intensity index (SII) and fat fraction (FF) in different histotypes were compared.

RESULTS

Only angiomyolipoma (AML), clear cell renal cell carcinoma (RCC), and papillary RCC were confirmed to contain fat. The FF of 16.8% can effectively differentiate AML from clear cell RCC, so did the SII of 9.2% can differentiate clear cell RCC from non-clear cell RCC and rare benign histotypes.

CONCLUSION

Dixon technique successfully evaluated the fat status and histotypes of renal masses.

Dual-Targeted Molecular Imaging of Cancer

Molecular imaging is critical to personalized and precision medicine. Although singly targeted imaging probes are making an impact both clinically and preclinically, molecular imaging strategies using bispecific probes have enabled improved visualization of cancer in recent years through synergistic targeting of two ligands. In this Focus on Molecular Imaging review, we outline how peptide-, antibody-, and nanoparticle-based platforms have affected this emerging strategy, providing examples and pointing out areas in which the greatest clinical impact may be realized.

Targeting PSMA with a Cu-64 Labeled Phosphoramidate Inhibitor for PET/CT Imaging of Variant PSMA-Expressing Xenografts in Mouse Models of Prostate Cancer

PURPOSE

Prostate-specific membrane antigen (PSMA) is highly up-regulated in prostate tumor cells, providing an ideal target for imaging applications of prostate cancer. CTT-1297 (IC50 = 27 nM) is an irreversible phosphoramidate inhibitor of PSMA that has been conjugated to the CB-TE1K1P chelator for incorporation of Cu-64. The resulting positron emission tomography (PET) agent, [(64)Cu]ABN-1, was evaluated for selective uptake both in vitro and in vivo in PSMA-positive cells of varying expression levels. The focus of this study was to assess the ability of [(64)Cu]ABN-1 to detect and distinguish varying levels of PSMA in a panel of prostate tumor-bearing mouse models.

PROCEDURES

CTT-1297 was conjugated to the CB-TE1K1P chelator using click chemistry and radiolabeled with Cu-64. Internalization and binding affinity of [(64)Cu]ABN-1 was evaluated in the following cell lines having varying levels of PSMA expression: LNCaP late-passage > LNCaP early passage ≈ C4-2B > CWR22rv1 and PSMA-negative PC-3 cells. PET/X-ray computed tomography imaging was performed in NCr nude mice with subcutaneous tumors of the variant PSMA-expressing cell lines.

RESULTS

[(64)Cu]ABN-1 demonstrated excellent uptake in PSMA-positive cells in vitro, with ∼80 % internalization at 4 h for each PSMA-positive cell line with uptake (fmol/mg) correlating to PSMA expression levels. The imaging data indicated significant tumor uptake in all models. The biodistribution for late-passage LNCaP (highest PSMA expression) demonstrated the highest specific uptake of [(64)Cu]ABN-1 with tumor-to-muscle and tumor-to-blood ratios of 30 ± 11 and 21 ± 7, respectively, at 24 h post-injection. [(64)Cu]ABN-1 cleared through all tissues except for PSMA-positive kidneys.

CONCLUSION

[(64)Cu]ABN-1 demonstrated selective uptake in PSMA-positive cells and tumors, which correlated to the level of PSMA expression. The data reported herein suggest that [(64)Cu]ABN-1 will selectively target and image variant PSMA expression and in the future will serve as a non-invasive method to follow the progression of prostate cancer in men.

Targeted Yttrium 89-Doxorubicin Drug-Eluting Bead-A Safety and Feasibility Pilot Study in a Rabbit Liver Cancer Model

The purpose of this article is to evaluate feasibility and safety of the cancer targeting (radio)-chemoembolization drug-eluting bead (TRCE-DEB) concept drug SW43-DOX-L-NETA(⁸⁹Y) DEB for the intra-arterial treatment of VX2 rabbit liver tumors. The treatment compound comprises of the sigma-2 receptor ligand SW43 for cancer targeting, doxorubicin (DOX), and ⁸⁹yttrium (⁸⁹Y) as nonradioactive surrogate for therapeutic (yttrium-90, lutetium-177) and imaging (yttrium-86) radioisotopes via the chelator L-NETA. Ten New Zealand white rabbits with VX2 tumor allografts were used. SW43-DOX-⁸⁹Y was synthesized, loaded onto DEB (100 μL; 100-300 μm), and administered intra-arterially in six rabbits at increasing doses (0.2-1.0 mg/kg). As controls, two rabbits each received either doxorubicin IV (0.3 mg/kg) or no treatment. Consecutive serum analysis for safety and histopathological evaluation after sacrifice were performed. One-Way ANOVA incl. Bonferroni Post-Hoc test was performed to compare groups. Targeted compound synthesis, loading onto DEB, and intra-arterial administration were feasible and successful in all cases. Serum liver enzyme levels increased in a dose dependent manner within 24 h and normalized within 3 days for 0.2/0.6 mg/kg SW43-DOX-⁸⁹Y loaded onto DEB. The two rabbits treated with 1 mg/kg SW43-DOX-⁸⁹Y had to be euthanized after 3/24 h due to worsening general condition. Histopathological necrosis increased over time in a dose depended manner with 95-100% tumor necrosis 3-7 days post treatment (0.6 mg/kg). SW43-DOX-⁸⁹Y loaded onto DEB can be formulated and safely administered at a concentration of 0.6 mg/kg. Loading with radioactive isotopes (e.g., ⁸⁶yttrium/⁹⁰yttrium/¹⁷⁷lutetium) to synthesize the targeted radio-chemoembolization drug-eluting bead (TRCE-DEB) concept drug is feasible.

Preclinical immunoPET/CT imaging using Zr-89-labeled anti-PD-L1 monoclonal antibody for assessing radiation-induced PD-L1 upregulation in head and neck cancer and melanoma

Radiation therapy (RT) can induce upregulation of programmed death ligand 1 (PD-L1) on tumor cells or myeloid cells, which may affect response to PD-1-based immunotherapy. PD-L1 upregulation during RT is a dynamic process that has been difficult to monitor during treatment. The aim of this study was to evaluate the RT-induced PD-L1 upregulation in the tumor and its microenvironment using immunoPET/CT imaging of two syngeneic murine tumor models (HPV+ head and neck squamous cell carcinoma (HNSCC) or B16F10 melanoma). Tumors were established in two locations per mouse (neck and flank), and fractionated RT (2 Gy × 4 or 2 Gy × 10) was delivered only to the neck tumor, alone or during anti-PD-1 mAb immunotherapy. PD-L1 expression was measured by PET/CT imaging using Zr-89 labeled anti-mouse PD-L1 mAb, and results were validated by flow cytometry. PET/CT imaging demonstrated significantly increased tracer uptake in irradiated neck tumors compared with non-irradiated flank tumors. Ex vivo analysis by biodistribution and flow cytometry validated PD-L1 upregulation specifically in irradiated tumors. In the HNSCC model, RT-induced PD-L1 upregulation was only observed after 2 Gy × 10 fractionated RT, while in the B16F10 model upregulation of PD-L1 occurred after 2 Gy × 4 fractionated RT. Fractionated RT, but not anti-PD-1 therapy, upregulated PD-L1 expression on tumor and infiltrating inflammatory cells in murine models, which could be non-invasively monitored by immunoPET/CT imaging using Zr-89 labeled anti-mouse PD-L1 mAb, and differentially identified anti-PD-1 responsive as well as selectively irradiated tumors in vivo.

In vitro biologic efficacy of sunitinib drug-eluting beads on human colorectal and hepatocellular carcinoma-A pilot study

Purpose

Sunitinib drug eluting beads (DEB) are a novel anti-angiogenic bead preparation for use in transarterial chemoembolization. However, systematic studies of sunitinib DEB’s effect on cancer cells have not been reported. Herein, we assess their direct biologic efficacy against carcinoma cell lines and correlate cell viability with drug release in vitro.

Materials and methods

Sunitinib-HCl (10mg/mL) in Milli-Q water was mixed with LC Bead® 300–500μm (Biocompatibles UK Ltd.). Loading and release were assessed by measurement of drug UV absorbance using UV-visible spectrophotometer. Viability of human colorectal cancer (CRC, HCT116 and HT29) and hepatocellular carcinoma (HCC, HepG2) cells upon exposure to sunitinib DEB was measured using a bioluminescent assay. Drug concentration during exposure was quantified using HPLC.

Results

When added to cultured HepG2 cells, sunitinib DEB rapidly inhibited viability with a significant decrease observed within 1 hour of incubation. Viability of HCT116 and HT29 cells decreased relatively slower, with significant reductions observed after 8 and 24 hours, respectively. After 24 hours there was nearly complete inhibition of all three cell lines. There was no difference in viability observed between cells treated with 5 μl, 10 μL, or 20 μL of sunitinib DEB. HPLC analysis of the cell culture supernatant demonstrated saturation of the cell medium within approximately 4 hours for each amount added, with sunitinib achieving a final concentration of 17.61 μM (SE ±1.01).

Conclusions

Sunitinib can be efficiently loaded to and released from LC beads, and the resulting sunitinib DEB demonstrate strong in vitro inhibition of human CRC and HCC cells.

Effects of cryopreservation on ultrastructural morphology of white shrimp (Litopenaeus vannamei) sperm

BACKGROUND

The structural integrity of a spermatozoon is very important for the processes of fertilization and embryo development.

OBJECTIVE

To provide valuable data for developing better cryopreservation techniques for shrimp sperm.

MATERIALS AND METHODS

Using scanning electron microscopy and transmission electron microscopy, we examined the morphological alteration of Litopenaeus vannamei sperm after cryopreservation with different concentrations of dimethylsulfoxide (DMSO).

RESULTS

We found that the damaged post-thaw sperm presented either vesiculated acrosomal contents, wrinkled membranes, perforated membranes, and loss of the acrosomal spike. The seriously damaged sperm showed missing acrosomal spikes, deformed nuclei, burst nuclear membranes, and vacuolated nuclei. In addition, we found that the post-thaw sperm stored with 5% DMSO had the highest viability rate and lowest DNA damage coefficient by eosin-nigrosin staining and comet assay.

CONCLUSION

Our results suggested that cryopreservation has deleterious effects on ultrastructural morphology of L. vannamei sperm, especially on acrosomal spikes and membranes.

Abstract 2071: SW43-DOX - a potential new targeted drug for the treatment of liver malignancies - An in vitro evaluation of receptor affinity and tumor internalization

Purpose: The σ2-receptor is known to be overexpressed on many rapidly growing cancer cells, thus represents a tumor biomarker and is potentially attractive for targeted tumor therapy. We have synthesized the conjugate SW43-DOX consisting of the σ2-receptor agonist SW43 and the anticancer agent Doxorubicin (DOX). The purpose of this study was to compare the half maximal effective concentration (EC50) of SW43-DOX and DOX and to evaluate the receptor affinity and internalization of SW43-DOX in hepatocellular carcinoma and other cancer cell lines in vitro.

Material & Methods: SW43 was synthesized and conjugated with Doxorubicin (A Chemtek Inc.) For saturation binding & internalization assays, the chelator L-NETA was attached & loaded with Lu177. Hep G2, Hep 3B, Panc-1 & HT-29 cell lines were evaluated. EC50 was assessed by treatment with various concentrations ranging from 0.5-700 μM of SW43-DOX/Doxorubicin (CellTiter-Glo®; Promega). Saturation binding assay: σ2-receptor blocking was achieved with 10-100 μM SW43 for 15 min. at RT prior to adding 1-300 μM SW43-DOX-Lu177 in HBSS buffer (+0.1% BSA) incubating for 3.5h on ice. Internalization assay: After receptor blocking (7.5 μM SW43; 15 min.), cells were incubated with 75 nM SW43-DOX-Lu177 for .5, 1 & 2h at 37°C/5% CO2. The cell surface bound fraction from the internalization assay was scavenged by incubation with HBSS (+20 mM NaOAc; pH4.0; 10 min; 37°C/5% CO2). Cells were lysed with 0.5% SDS, radioactivity measured (Cobra -counter, Packard Bell) & normalized to whole cell protein. Statistics: EC50: Dose response non-linear fitting model; Internalization: ANOVA + Bonferroni post-hoc test, Saturation binding: One site saturation non-linear regression fit model. Prism V6.0.

Results: EC50 showed lower needed concentration (μM) for SW43-DOX compared to Doxorubicin: Hep G2 (12.0 (95%CI: 10.3-13.9) vs. 81.5 (95%CI: 66.7-99.5); p&lt;0.001), Hep 3B (8.0 (95%CI: 7.2-9) vs. 17.6 (95%CI: 14.1-22); p&lt;0.001), Panc-1 (21.59 (95%CI: 15.44-30.2) vs. 64.5 (95%CI: 50.3-82.6); p = 0.31), and HT-29 (20.7 (95%CI: 18.3-23.3) vs. 179.8 (95%CI: 65.9-593.5); p&lt;0.001). Maximal specific cell surface binding capacity (Bmax; pmol/mg): Hep G2 (21.5; 95%CI: 14.3-28.6), Hep 3B (35.2; 95%CI: 27.9-42.5), Panc-1 (66.5; 95%CI: 51.6-78.2) & HT-29 (33.4; 95%CI: 8.43-58.5). Specific binding affinity (KD) in nM: Hep G2 (49.2; 95%CI: 2.2-96.3), Hep 3B (40.8; 95%CI: 13.4-68.1), Panc-1 (96.4; 95%CI: 51.4-141.5), HT-29 (31.3; 95%CI: -40.5-84.4). Specific internalization was evident at all time points for all cell lines (p&lt;0.05). Specific internalization (pmol/mg ±SD) after 2h was 29.5 ±6.6 (Panc-1), 10.3 ±1.6 (HT-29), 18.2 ±2.36 (Hep G2) & 30.7 ±8.2 (Hep 3B).

Conclusion: SW43-DOX exerts a higher antitumoral effect than Doxorubicin & binds specifically onto the cell surface with high affinity & subsequently specific uptake via the σ2-receptor.

Citation Format: Johannes M. Ludwig, Yongkang Gai, Sun Lingyi, Dexing Zeng, Hyun S. Kim. SW43-DOX - a potential new targeted drug for the treatment of liver malignancies - An in vitro evaluation of receptor affinity and tumor internalization. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2071.

New Bifunctional Chelator p-SCN-PhPr-NE3TA for Copper-64: Synthesis, Peptidomimetic Conjugation, Radiolabeling, and Evaluation for PET Imaging

Bifunctional chelators play an important role in developing metallic radionuclide-based radiopharmaceuticals. In this study, a new bifunctional ligand, p-SCN-PhPr-NE3TA, was synthesized and conjugated to a very late antigen-4 targeting peptidomimetic, LLP2A, for evaluating its application in (64)Cu-based positron emission tomography (PET) imaging. The new ligand exhibited strong selective coordination of Cu(II), leading to a robust Cu complex, even in the presence of 10-fold Fe(III). The LLP2A conjugate of p-SCN-PhPr-NE3TA was prepared and successfully labeled with (64)Cu under mild conditions. The conjugate (64)Cu-NE3TA-PEG4-LLP2A showed significantly higher specific activity, compared with (64)Cu-NOTA-PEG4-LLP2A, while maintaining comparable serum stability. Subsequent biodistribution studies and PET imaging in mice bearing B16F10 xenografts confirmed its favorable in vivo performance and high tumor uptake with low background, rendering p-SCN-PhPr-NE3TA a promising bifunctional chelator for (64)Cu-based radiopharmaceuticals.

SW43-DOX ± loading onto drug-eluting bead, a potential new targeted drug delivery platform for systemic and locoregional cancer treatment - An in vitro evaluation

Treatment of unresectable primary cancer and their distant metastases, with the liver representing one of the most frequent location, is still plagued by insufficient treatment success and poor survival rates. The Sigma-2 receptor is preferentially expressed on many tumor cells making it an appealing target for therapy. Thus, we developed a potential targeted drug conjugate consisting of the Sigma-2 receptor ligand SW43 and Doxorubicin (SW43-DOX) for systemic cancer therapy and for locoregional treatment of primary and secondary liver malignancies when loaded onto drug-eluting bead (DEB) which was compared in vitro to the treatment with Doxorubicin alone. SW43-DOX binds specifically to the Sigma-2 receptor expressed on hepatocellular (Hep G2, Hep 3B), pancreatic (Panc-1) and colorectal (HT-29) carcinoma cell lines with high affinity and subsequent early specific internalization. Free SW43-DOX showed superior concentration and time depended cancer toxicity than treatment with Doxorubicin alone. Action mechanisms analysis revealed an apoptotic cell death with increased caspase 3/7 activation and reactive oxygen species (ROS) production. Only ROS scavenging with α-Tocopherol, but not the caspase inhibition (Z-VAD-FMK), partly reverted the effect. SW43-DOX could successfully be loaded onto DEB and showed prolonged eluting kinetics compared to Doxorubicin. SW43-DOX loaded DEB vs. Doxorubicin loaded DEB showed a significantly greater time dependent toxicity in all cell lines. In conclusion, the novel conjugate SW43-DOX ± loading onto DEB is a promising drug delivery platform for targeted systemic and locoregional cancer therapy.

Novel Strategy for Preparing Dual-Modality Optical/PET Imaging Probes via Photo-Click Chemistry

Preparation of small molecule based dual-modality probes remains a challenging task due to the complicated synthetic procedure. In this study, a novel concise and generic strategy for preparing dual-modality optical/PET imaging probes via photo-click chemistry was developed, in which the diazole photo-click linker functioned not only as a bridge between the targeting-ligand and the PET imaging moiety, but also as the fluorophore for optical imaging. A dual-modality AE105 peptidic probe was successfully generated via this strategy and subsequently applied in the fluorescent staining of U87MG cells and the (68)Ga based PET imaging of mice bearing U87MG xenograft. In addition, dual-modality monoclonal antibody cetuximab has also been generated via this strategy and labeled with (64)Cu for PET imaging studies, broadening the application of this strategy to include the preparation of macromolecule based imaging probes.