Development of small-molecular-based radiotracers for PET imaging of PD-L1 expression and guiding the PD-L1 therapeutics

PURPOSE

Programmed cell death protein ligand 1 (PD-L1) is a crucial biomarker for immunotherapy. However, nearly 70% of patients do not respond to PD-L1 immune checkpoint therapy. Accurate monitoring of PD-L1 expression and quantification of target binding during treatment are essential. In this study, a series of small-molecule radiotracers were developed to assess PD-L1 expression and direct immunotherapy.

METHODS

Radiotracers of [68Ga]Ga-D-PMED, [68Ga]Ga-D-PEG-PMED, and [68Ga]Ga-D-pep-PMED were designed based on a 2-methyl-3-biphenyl methanol scaffold and successfully synthesized. Cellular experiments and molecular docking assays were performed to determine their specificity for PD-L1. PD-L1 status was investigated via positron emission tomography (PET) imaging in MC38 tumor models. PET imaging of [68Ga]Ga-D-pep-PMED was performed to noninvasively quantify PD-L1 blocking using an anti-mouse PD-L1 antibody (PD-L1 mAb).

RESULTS

The radiosyntheses of [68Ga]Ga-D-PMED, [68Ga]Ga-D-PEG-PMED, and [68Ga]Ga-D-pep-PMED were achieved with radiochemical yields of 87 ± 6%, 82 ± 4%, and 79 ± 9%, respectively. In vitro competition assays demonstrated their high affinities (the IC50 values of [68Ga]Ga-D-PMED, [68Ga]Ga-D-PEG-PMED, and [68Ga]Ga-D-pep-PMED were 90.66 ± 1.24, 160.8 ± 1.35, and 51.6 ± 1.32 nM, respectively). At 120 min postinjection (p.i.) of the radiotracers, MC38 tumors displayed optimized tumor-to-muscle ratios for all radioligands. Owing to its hydrophilic modification, [68Ga]Ga-D-pep-PMED had the highest target-to-nontarget (T/NT) ratio of approximately 6.2 ± 1.2. Interestingly, the tumor/liver ratio was hardly affected by different concentrations of the inhibitor BMS202. We then evaluated the impacts of dose and time on accessible PD-L1 levels in the tumor during anti-mouse PD-L1 antibody treatment. The tumor uptake of [68Ga]Ga-D-pep-PMED significantly decreased with increasing PD-L1 mAb dose. Moreover, after 8 days of treatment with a single antibody, the uptake of [68Ga]Ga-D-pep-PMED in the tumor significantly increased but remained lower than that in the saline group.

CONCLUSION

PET imaging with [68Ga]Ga-D-pep-PMED, a small-molecule radiotracer, is a promising tool for evaluating PD-L1 expression and quantifying the target blockade of PD-L1 to assist in the development of effective therapeutic regimens.

Application of deep learning in radiation therapy for cancer

In recent years, with the development of artificial intelligence, deep learning has been gradually applied to clinical treatment and research. It has also found its way into the applications in radiotherapy, a crucial method for cancer treatment. This study summarizes the commonly used and latest deep learning algorithms (including transformer, and diffusion models), introduces the workflow of different radiotherapy, and illustrates the application of different algorithms in different radiotherapy modules, as well as the defects and challenges of deep learning in the field of radiotherapy, so as to provide some help for the development of automatic radiotherapy for cancer.

Generation of induced pluripotent stem cells from rat fibroblasts and optimization of its differentiation into mature functional neurons

BACKGROUND

Induced pluripotent stem cells (iPSCs) derived neural stem cells (NSCs) provide a potential for autologous neural transplantation therapy following neurological insults. Thus far, in preclinical studies the donor iPSCs-NSCs are mostly of human or mouse origin with concerns centering around graft rejection when applied to rat brain injury models. For better survival and integration of transplanted cells in the injured brain in rat models, use of rat-iPSC-NSCs and in combination with biomaterials is of advantageous. Herein, we report a detailed method in generating rat iPSCs with improved reprogramming efficiency and differentiation into neurons.

NEW METHOD

Rat fibroblasts were reprogrammed into iPSCs with polybrene and EF1α-STEMCCA-LoxP lentivirus vector. Pluripotency characterization, differentiation into neuronal linage cells were assessed with RT-qPCR, Western blotting, immunostaining and patch-clamp methods. Cells were cultured in a custom-designed integrin array system as well as in a hydrogel-based 3D condition.

RESULTS

We describe a thorough method for the generation of rat-iPSC-NSCs, and identify integrin αvβ8 as a substrate for the optimal growth of rat-iPSC-NSCs. Furthermore, with hydrogel as the supporting biomaterial in the 3-D culture, when combined with integrin αvβ8 binding peptide, it forms a conducive environment for optimal growth and differentiation of iPSC-NSCs into mature neurons.

COMPARISON WITH EXISTING METHODS

Published studies about rat-iPSC-NSCs are rare. This study provides a detailed protocol for the generation of rat iPSC-NSCs and optimal growth conditions for neuronal differentiation. Our method is useable for studies to assess the utility of rat iPSC-NSCs for neural transplantation in rat brain injury models.

Synthesis, preclinical, and initial clinical evaluation of integrin αVβ3 and gastrin-releasing peptide receptor (GRPR) dual-targeting radiotracer [68Ga]Ga-RGD-RM26-03

Integrin receptor αvβ3 and gastrin-releasing peptide receptor (GRPR) expression of tumors could be detected using PET imaging with radiolabeled Arg-Gly-Asp (RGD) and the antagonistic bombesin analog RM26, respectively. The purpose of this study was to investigate the dual receptor-targeting property of the heterodimer RGD-RM26-03 (denoted as LNC1015), demonstrate the tumor diagnostic value of [68Ga]Ga-LNC1015 in preclinical experiments, and evaluate its preliminary clinical feasibility.

METHODS

LNC1015 was designed and synthesized by linking cyclic RGD and the RM26 peptide. Preclinical pharmacokinetics were detected in a PC3 xenograft model using microPET and biodistribution studies. The clinical feasibility of [68Ga]Ga-LNC1015 PET/CT was performed in patients with breast cancer, and the results were compared with those of 18F-fluorodeoxyglucose (FDG).

RESULTS

[68Ga]Ga-LNC1015 had good stability in saline for at least 2 h, and favorable binding affinity and specificity were demonstrated in vitro and in vivo. The tumor uptake and retention of [68Ga]Ga-LNC1015 during PET imaging were improved compared with its monomeric counterparts [68Ga]Ga-RGD and [68Ga]Ga-RM26 at all the time points examined. In our initial clinical studies, the tumor uptake and tumor-to-background ratio (TBR) of primary and metastatic lesions in [68Ga]Ga-LNC1015 PET/CT were significantly higher than those in [18F]FDG PET/CT, resulting in high lesion detection rate and tumor delineation.

CONCLUSION

The dual targeting radiotracer [68Ga]Ga-LNC1015 showed significantly improved tumor uptake and retention, as well as lower liver uptake than [68Ga]Ga-RGD and [68Ga]Ga-RM26 monomer. The first-in-human study showed high TBRs in patients, suggesting favorable pharmacokinetics and high clinical feasibility for PET/CT imaging of cancer.

Biomimetic crimped/aligned microstructure to optimize the mechanics of fibrous hybrid materials for compliant vascular grafts

The precise mechanical properties of many tissues are highly dependent on both the composition and arrangement of the nanofibrous extracellular matrix. It is well established that collagen nanofibers exhibit a crimped microstructure in several tissues such as blood vessel, tendon, and heart valve. This collagen fiber arrangement results in the classic non-linear 'J-shaped' stress strain curve characteristic of these tissues. Synthetic biomimetic fibrous materials with a crimped microstructure similar to natural collagen demonstrate similar mechanical properties to natural tissues. The following work describes a nanofabrication method based on electrospinning used to fabricate two component hybrid electrospun fibrous materials that mimic the microstructure and mechanical properties of vascular tissue. The properties of these samples can be precisely and predictably optimized by modifying fabrication parameters. Tubular grafts with biomimetic microstructure were constructed to demonstrate the potential of this fabrication method in vascular graft replacement applications. It was possible to closely match both the overall geometry and the compliance of specific blood vessels by optimizing graft microstructure.

Myokines and Biomarkers of Frailty in Older Inpatients with Undernutrition: A Prospective Study

BACKGROUND

Population aging might increase the prevalence of undernutrition in older people, which increases the risk of frailty. Numerous studies have indicated that myokines are released by skeletal myocytes in response to muscular contractions and might be associated with frailty. This study aimed to evaluate whether myokines are biomarkers of frailty in older inpatients with undernutrition.

METHODS

The frailty biomarkers were extracted from the Gene Expression Omnibus and Genecards datasets. Relevant myokines and health-related variables were assessed in 55 inpatients aged ≥ 65 years from the Peking Union Medical College Hospital prospective longitudinal frailty study. Serum was prepared for enzyme-linked immunosorbent assay using the appropriate kits. Correlations between biomarkers and frailty status were calculated by Spearman's correlation analysis. Multiple linear regression was performed to investigate the association between factors and frailty scores.

RESULTS

The prevalence of frailty was 13.21%. The bioinformatics analysis indicated that leptin, adenosine 5'-monophosphate-activated protein kinase (AMPK), irisin, decorin, and myostatin were potential biomarkers of frailty. The frailty group had significantly higher concentrations of leptin, AMPK, and MSTN than the robust group (p < 0.05). AMPK was significantly positively correlated with frailty (p < 0.05). The pre-frailty and frailty groups had significantly lower concentrations of irisin than the robust group (p < 0.05), whereas the DCN concentration did not differ among the groups. Multiple linear regression suggested that the 15 factors influencing the coefficients of association, the top 50% were the ADL score, MNA-SF score, serum albumin concentration, urination function, hearing function, leptin concentration, GDS-15 score, and MSTN concentration.

CONCLUSIONS

Proinflammatory myokines, particularly leptin, myostatin, and AMPK, negatively affect muscle mass and strength in older adults. ADL and nutritional status play major roles in the development of frailty. Our results confirm that identification of frailty relies upon clinical variables, myokine concentrations, and functional parameters, which might enable the identification and monitoring of frailty.

In Vivo Comparative Study of Radioiodinated Folate Receptor Targeting Albumin Probes for Atherosclerosis Plaque Imaging

The objective of this study is to compare a series of albumin-based folate radiotracers for the potential imaging of folate receptor (FR) positive macrophages in advanced atherosclerotic plaques. Diversified radioiodinated FR-targeting albumin-binding probes ([131I]IBAbHF, [131I]IBNHF, and [131I]HF) were developed through various strategies. Among the three radiotracers, [131I]IBAbHF and [131I]IBNHF showed excellent in vitro stability (>98%) in saline and PBS 7.4 for 24 h. Also, good stability of [131I]IBNHF in mouse serum albumin was monitored using an HSA ELISA kit. The experiments in Raw264.7 macrophages activated by ox-LDL confirmed the specificity of tracers for FR-β. Biodistribution studies of radiotracers were performed to verify the prolonged blood half-life. Prolonged blood half-lives of [131I]IBAbHF, [131I]HF, and [131I]IBNHF were 17.26 ± 4.29, 6.33 ± 2.64, and 5.50 ± 1.26 h, respectively. SPECT-CT imaging of ApoE-/- mice at different stages was performed to evaluate the progression and monitor the prognosis of AS. Evident [131I]IBNHF uptake in atherosclerotic lesions could be observed along with a low background signal. In summary, we demonstrated a proof-of-concept of albumin-based radioligands for FR-targeting atherosclerosis imaging and found that different incorporation of radioiodinated groups resulted in different pharmacokinetic properties. Among these candidate compounds, [131I]IBNHF would be a satisfactory radiotracer for SPECT imaging of atherosclerosis.

Use of TSAR, Thermal Shift Analysis in R, to identify Folic Acid as a Molecule that Interacts with HIV-1 Capsid

Thermal shift assay (TSA) is a versatile biophysical technique for studying protein interactions. Here, we report a free, open-source software tool TSAR (Thermal Shift Analysis in R) to expedite and automate the analysis of thermal shift data derived either from individual experiments or large screens of chemical libraries. The TSAR package incorporates multiple, dynamic workflows to facilitate the analysis of TSA data and returns publication-ready graphics or processed results. Further, the package includes a graphic user interface (GUI) that enables easy use by non-programmers, aiming to simplify TSA analysis while diversifying visualization. To exemplify the utility of TSAR we screened a chemical library of vitamins to identify molecules that interact with the capsid protein (CA) of human immunodeficiency virus type 1 (HIV-1). Our data show that hexameric CA interacts with folic acid in vitro.

A Head-to-Head Comparison of 68Ga-LNC1007 and 2-18F-FDG/68Ga-FAPI-02 PET/CT in Patients With Various Cancers

OBJECTIVES

This head-to-head comparison study was designed to investigate the radiotracer uptake and clinical feasibility of using 68Ga-LNC1007, to detect the primary and metastatic lesions in patients with various types of cancer, and to compare the results with those of 2-18F-FDG PET/CT and 68Ga-FAPI-02 PET/CT.

PATIENTS AND METHODS

Sixty-one patients with 10 different kinds of cancers were enrolled in this study. Among them, 50 patients underwent paired 68Ga-LNC1007 and 2-18F-FDG PET/CT, and the other 11 patients underwent paired 68Ga-LNC1007 and 68Ga-FAPI-02 PET/CT. The final diagnosis was based on histopathological results and diagnostic radiology. Immunohistochemistry for FAP and integrin αvβ3 was performed in 24 primary tumors.

RESULTS

68Ga-LNC1007 PET/CT detected all 55 primary tumors, whereas 2-18F-FDG PET/CT was visually positive for 45 primary tumors (P = 0.002). Furthermore, subgroup analysis showed that 68Ga-LNC1007 PET/CT was superior to 2-18F-FDG PET/CT in diagnosing renal cell carcinomas and hepatocellular carcinomas. For metastatic tumors, 68Ga-LNC1007 PET/CT revealed more PET-positive lesions and higher SUVmax for skeletal metastases and peritoneal metastases compared with 2-18F-FDG. The SUVmax and tumor-to-background ratio of primary tumors on 68Ga-LNC1007 PET/CT were much higher than those on 68Ga-FAPI-02 PET/CT, the same was also observed for metastatic tumors. Immunohistochemical results showed that the SUVmean quantified from 68Ga-LNC1007 PET was correlated with FAP expression level (r = 0.564, P = 0.005).

CONCLUSIONS

68Ga-LNC1007 is a promising new diagnostic PET tracer for imaging of various kinds of malignant lesions. It may be a better alternative to 2-18F-FDG for diagnosing renal cell carcinoma, hepatocellular carcinoma, skeletal metastases, and peritoneal metastases.

Single-cell dissection of cervical cancer reveals key subsets of the tumor immune microenvironment

The tumor microenvironment (TME) directly determines patients' outcomes and therapeutic efficiencies. An in-depth understanding of the TME is required to improve the prognosis of patients with cervical cancer (CC). This study conducted single-cell RNA and TCR sequencing of six-paired tumors and adjacent normal tissues to map the CC immune landscape. T and NK cells were highly enriched in the tumor area and transitioned from cytotoxic to exhaustion phenotypes. Our analyses suggest that cytotoxic large-clone T cells are critical effectors in the antitumor response. This study also revealed tumor-specific germinal center B cells associated with tertiary lymphoid structures. A high-germinal center B cell proportion in patients with CC is predictive of improved clinical outcomes and is associated with elevated hormonal immune responses. We depicted an immune-excluded stromal landscape and established a joint model of tumor and stromal cells to predict CC patients' prognosis. The study revealed tumor ecosystem subsets linked to antitumor response or prognosis in the TME and provides information for future combinational immunotherapy.

Development of [177Lu]Lu-LNC1003 for radioligand therapy of prostate cancer with a moderate level of PSMA expression

PURPOSE

Evans blue as an albumin binder has been widely used to improve pharmacokinetics and enhance tumor uptake of radioligands, including prostate-specific membrane antigen (PSMA) targeting agents. The goal of this study is to develop an optimal Evans blue-modified radiotherapeutic agent that could maximize the absolute tumor uptake and tumor absorbed dose thus the therapeutic efficacy to allow treatment of tumors even with moderate level of PSMA expression.

METHODS

[177Lu]Lu-LNC1003 was synthesized based on PSMA-targeting agent and Evans blue. Binding affinity and PSMA targeting specificity were verified through cell uptake and competition binding assay in 22Rv1 tumor model that has moderate level of PSMA expression. SPECT/CT imaging and biodistribution studies in 22Rv1 tumor-bearing mice were performed to evaluate the preclinical pharmacokinetics. Radioligand therapy studies were conducted to systematically assess the therapeutic effect of [177Lu]Lu-LNC1003.

RESULTS

LNC1003 showed high binding affinity (IC50 = 10.77 nM) to PSMA in vitro, which was comparable with that of PSMA-617 (IC50 = 27.49 nM) and EB-PSMA-617 (IC50 = 7.91 nM). SPECT imaging of [177Lu]Lu-LNC1003 demonstrated significantly improved tumor uptake and retention as compared with [177Lu]Lu-EB-PSMA and [177Lu]Lu-PSMA-617, making it suitable for prostate cancer therapy. Biodistribution studies further confirmed the remarkably higher tumor uptake of [177Lu]Lu-LNC1003 (138.87 ± 26.53%ID/g) over [177Lu]Lu-EB-PSMA-617 (29.89 ± 8.86%ID/g) and [177Lu]Lu-PSMA-617 (4.28 ± 0.25%ID/g) at 24 h post-injection. Targeted radioligand therapy results showed noteworthy inhibition of 22Rv1 tumor growth after administration of a single dose of 18.5 MBq [177Lu]Lu-LNC1003. There was no obvious antitumor effect after [177Lu]Lu-PSMA-617 treatment under the same condition.

CONCLUSION

In this study, [177Lu]Lu-LNC1003 was successfully synthesized with high radiochemical purity and stability. High binding affinity and PSMA targeting specificity were identified in vitro and in vivo. With greatly enhanced tumor uptake and retention, [177Lu]Lu-LNC1003 has the potential to improve therapeutic efficacy using significantly lower dosages and less cycles of 177Lu that promises clinical translation to treat prostate cancer with various levels of PSMA expression.

Nanoparticle-Based Drug Delivery Systems: An Inspiring Therapeutic Strategy for Neurodegenerative Diseases

Neurodegenerative diseases are common, incurable neurological disorders with high prevalence, and lead to memory, movement, language, and intelligence impairments, threatening the lives and health of patients worldwide. The blood-brain barrier (BBB), a physiological barrier between the central nervous system and peripheral blood circulation, plays an important role in maintaining the homeostasis of the intracerebral environment by strictly regulating the transport of substances between the blood and brain. Therefore, it is difficult for therapeutic drugs to penetrate the BBB and reach the brain, and this affects their efficacy. Nanoparticles (NPs) can be used as drug transport carriers and are also known as nanoparticle-based drug delivery systems (NDDSs). These systems not only increase the stability of drugs but also facilitate the crossing of drugs through the BBB and improve their efficacy. In this article, we provided an overview of the types and administration routes of NPs, highlighted the preclinical and clinical studies of NDDSs in neurodegenerative diseases, and summarized the combined therapeutic strategies in the management of neurodegenerative diseases. Finally, the prospects and challenges of NDDSs in recent basic and clinical research were also discussed. Above all, NDDSs provide an inspiring therapeutic strategy for the treatment of neurodegenerative diseases.

Clinical Evaluation of 68Ga-FAPI-RGD for Imaging of Fibroblast Activation Protein and Integrin αvβ3 in Various Cancer Types

Radiolabeled fibroblast activation protein (FAP) inhibitors (FAPIs) and Arg-Gly-Asp (RGD) peptides have been extensively investigated for imaging of FAP- and integrin α_vβ₃-positive tumors. In this study, a FAPI-RGD heterodimer was radiolabeled with ⁶⁸Ga and evaluated in patients with cancer. We hypothesized that the heterodimer, recognizing both FAP and integrin α_vβ₃, would be advantageous because of its dual-receptor-targeting property. Methods: The effective dose of ⁶⁸Ga-FAPI-RGD was evaluated in 3 healthy volunteers. The clinical feasibility of ⁶⁸Ga-FAPI-RGD PET/CT was evaluated in 22 patients with various types of cancer, and the results were compared with those of ¹⁸F-FDG and ⁶⁸Ga-FAPI-46. Results: ⁶⁸Ga-FAPI-RGD was tolerated well, with no adverse events in any of the healthy volunteers or patients. The effective dose from ⁶⁸Ga-FAPI-RGD PET/CT was 1.01 × 10^-2 mSv/MBq. In clinical investigations with different types of cancer, the radiotracer uptake and tumor-to-background ratio (TBR) of primary and metastatic lesions in ⁶⁸Ga-FAPI-RGD PET/CT were significantly higher than those in ¹⁸F-FDG PET/CT (primary tumors: SUV_max, 18.0 vs. 9.1 [P < 0.001], and TBR, 15.2 vs. 5.5 [P < 0.001]; lymph node metastases: SUV_max, 12.1 vs. 6.1 [P < 0.001], and TBR, 13.3 vs. 4.1 [P < 0.001]), resulting in an improved lesion detection rate and tumor delineation, particularly for the diagnosis of lymph node (99% vs. 91%) and bone (100% vs. 80%) metastases. ⁶⁸Ga-FAPI-RGD PET/CT also yielded a higher radiotracer uptake and TBR than ⁶⁸Ga-FAPI-46 PET/CT did. Conclusion: ⁶⁸Ga-FAPI-RGD exhibited improved tumor uptake and TBR compared with ¹⁸F-FDG and ⁶⁸Ga-FAPI PET/CT. This study demonstrated the safety and clinical feasibility of ⁶⁸Ga-FAPI-RGD PET/CT for imaging of various types of cancer.

[Oncologic outcomes of surgical treatments of advanced sinonasal malignancies]

Objective: To investigate the prognoses of advanced (T3-T4) sinonasal malignancies (SNM). Methods: The clinical data of 229 patients with advanced (T3-4) SNM who underwent surgical treatments in the First Affiliated Hospital of Sun Yat-sen University from 2000 to 2018 were retrospectively analyzed, including 162 males and 67 females, aged (46.8±18.5) years old. Among them, 167 cases received endoscopic surgery alone, 30 cases received assisted incision endoscopic surgery, and 32 cases received open surgery. The Kaplan-Meier method was used to estimate the 3-year and 5-year overall survival (OS) and event-free survival (EFS). Univariate and multivariate Cox regression analyses were performed to explore significant prognostic factors. Results: The 3-year and 5-year OS were respectively 69.7% and 64.0%. The median OS time was 43 months. The 3-year and 5-year EFS were respectively 57.8% and 47.4%. The median EFS time was 34 months. The 5-year OS of the patients with epithelial-derived tumors was better than that of the patients with mesenchymal-derived tumors and malignant melanoma (5-year OS was respectively 72.3%, 47.8% and 30.0%, χ²=36.01, P<0.001). Patients with microscopically margin-negative resection (R0 resection) had the best prognosis, followed by macroscopically margin-negative resection (R1 resection), and debulking surgery was the worst (5-year OS was respectively 78.4%, 55.1% and 37.4%, χ²=24.63, P<0.001). There was no significant difference in 5-year OS between the endoscopic surgery group and the open surgery group (65.8% vs. 53.4%, χ²=2.66, P=0.102). Older patients had worse OS (HR=1.02, P=0.011) and EFS (HR=1.01, P=0.027). Patients receiving adjuvant therapy had a lower risk of death (HR=0.62, P=0.038). Patients with a history of nasal radiotherapy had a higher risk of recurrence (HR=2.48, P=0.002) and a higher risk of death (HR=2.03, P=0.020). Conclusion: For patients with advanced SNM, the efficacy of endoscopic surgery can be comparable to that of open surgery when presence of safe surgical margins, and a treatment plan based on transnasal endoscopic surgery as the main comprehensive treatment is recommended.

Association of pectoralis muscle area on computed tomography with airflow limitation severity and respiratory outcomes in COPD: A population-based prospective cohort study

BACKGROUND

Previous studies have shown that patients with chronic obstructive pulmonary disease (COPD) of severe or very severe airflow limitation have a reduced pectoralis muscle area (PMA), which is associated with mortality. However, whether patients with COPD of mild or moderate airflow limitation also have a reduced PMA remains unclear. Additionally, limited evidence is available regarding the associations between PMA and respiratory symptoms, lung function, computed tomography (CT) imaging, lung function decline, and exacerbations. Therefore, we conducted this study to evaluate the presence of PMA reduction in COPD and to clarify its associations with the referred variables.

METHODS

This study was based on the subjects enrolled from July 2019 to December 2020 in the Early Chronic Obstructive Pulmonary Disease (ECOPD) study. Data including questionnaire, lung function, and CT imaging were collected. The PMA was quantified on full-inspiratory CT at the aortic arch level using predefined -50 and 90 Hounsfield unit attenuation ranges. Multivariate linear regression analyses were performed to assess the association between the PMA and airflow limitation severity, respiratory symptoms, lung function, emphysema, air trapping, and the annual decline in lung function. Cox proportional hazards analysis and Poisson regression analysis were used to evaluate the PMA and exacerbations after adjustment.

RESULTS

We included 1352 subjects at baseline (667 with normal spirometry, 685 with spirometry-defined COPD). The PMA was monotonically lower with progressive airflow limitation severity of COPD after adjusting for confounders (vs. normal spirometry; Global Initiative for Chronic Obstructive Lung Disease [GOLD] 1: β=-1.27, P=0.028; GOLD 2: β=-2.29, P<0.001; GOLD 3: β=-4.88, P<0.001; GOLD 4: β=-6.47, P=0.014). The PMA was negatively associated with the modified British Medical Research Council dyspnea scale (β=-0.005, P=0.026), COPD Assessment Test score (β=-0.06, P=0.001), emphysema (β=-0.07, P<0.001), and air trapping (β=-0.24, P<0.001) after adjustment. The PMA was positively associated with lung function (all P<0.05). Similar associations were discovered for the pectoralis major muscle area and pectoralis minor muscle area. After the 1-year follow-up, the PMA was associated with the annual decline in the post-bronchodilator forced expiratory volume in 1 s percent of predicted value (β=0.022, P=0.002) but not with the annual rate of exacerbations or the time to first exacerbation.

CONCLUSION

Patients with mild or moderate airflow limitation exhibit a reduced PMA. The PMA is associated with airflow limitation severity, respiratory symptoms, lung function, emphysema, and air trapping, suggesting that PMA measurement can assist with COPD assessment.

Long-read sequencing reveals oncogenic mechanism of HPV-human fusion transcripts in cervical cancer

Integration of high-risk human papillomavirus (HPV) into the host genome is a crucial event for the development of cervical cancer, however, the underlying mechanism of HPV integration-driven carcinogenesis remains unknown. Here, we performed long-read RNA sequencing on 12 high-grade squamous intraepithelial lesions (HSIL) and cervical cancer patients, including 3 pairs of cervical cancer and corresponding para-cancerous tissue samples to investigate the full-length landscape of cross-species genome integrations. In addition to massive unannotated isoforms, transcriptional regulatory events, and gene chimerism, more importantly, we found that HPV-human fusion events were prevalent in HPV-associated cervical cancers. Combined with the genome data, we revealed the existence of a universal transcription pattern in these fusion events, whereby structurally similar fusion transcripts were generated by specific splicing in E6 and a canonical splicing donor site in E1 linking to various human splicing acceptors. Highly expressed HPV-human fusion transcripts, eg, HPV16 E6*I-E7-E1_SD880-human gene, were the key driver of cervical carcinogenesis, which could trigger overexpression of E6*I and E7, and destroy the transcription of tumor suppressor genes CMAHP, TP63 and P3H2. Finally, evidence from in vitro and in vivo experiments demonstrates that the novel read-through fusion gene mRNA, E1-CMAHP (E1C, formed by the integration of HPV58 E1 with CMAHP), existed in the fusion transcript can promote malignant transformation of cervical epithelial cells via regulating downstream oncogenes to participate in various biological processes. Taken together, we reveal a previously unknown mechanism of HPV integration-driven carcinogenesis and provide a novel target for the diagnosis and treatment of cervical cancer.

A simple method to isolate structurally and chemically intact brain vascular basement membrane for neural regeneration following traumatic brain injury

BACKGROUND

The brain vascular basement membrane (brain-VBM) is an important component of the brain extracellular matrix, and the three-dimensional structure of the cerebrovascular network nested with many cell-adhesive proteins may provide guidance for brain tissue regeneration. However, the potential of ability of brain-VBM to promote neural tissue regeneration has not been examined due to the technical difficulty of isolating intact brain-VBM.

METHODS

The present study developed a simple, effective method to isolate structurally and compositionally intact brain-VBM. Structural and component properties of the brain-VBM were characterized to confirm the technique. Seed cells were cocultured with brain-VBM in vitro to analyze biocompatibility and neurite extension. An experimental rat model of focal traumatic brain injury (TBI) induced by controlled cortical impact were conducted to further test the tissue regeneration ability of brain-VBM.

RESULTS

Brain-VBM isolated using genipin showed significantly improved mechanical properties, was easy to handle, supported high cell viability, exhibited strong cell adhesive properties, and promoted neurite extension and outgrowth. Further testing of the isolated brain-VBM transplanted at lesion sites in an experimental rat model of focal TBI demonstrated considerable promise for reconstructing a complete blood vessel network that filled in the lesion cavity and promoting repopulation of neural progenitor cells and neurons.

CONCLUSION

The technique allows isolation of intact brain-VBM as a 3D microvascular scaffold to support brain tissue regeneration following TBI and shows considerable promise for the production of naturally-derived biomaterials for neural tissue engineering.

Longitudinal MicroSPECT Imaging of Systemic Sclerosis Model Mice with [99mTc]Tc-HYNFA via Folate Receptor Targeting

Noninvasive single-photon emission computed tomography (SPECT) imaging with [^99mTc]Tc-HYNFA via folate receptor (FR) targeting was proposed to assess the inflammation and therapeutic effect of systemic sclerosis (SSc) in model mice. The radiochemical yield and purity of [^99mTc]Tc-HYNFA were over 95%, with a specific activity of about 9.36 ± 0.17 MBq/nmol. At the end of induction, the uptake ratios of bleomycin-injected regions on the back-to-muscle (R/M) and lung-to-muscle (L/M) derived from SPECT images were 7.27 ± 0.50 and 4.25 ± 0.15, respectively. The radioactivity uptakes could be blocked by excessive folic acid (FA), and R/M and L/M obviously decreased to 2.78 ± 0.57 and 2.51 ± 0.79, respectively. R/M (2.22 ± 0.71) and L/M (1.62 ± 0.28) decreased very close to those of the control mice group (R/M = 1.99 ± 0.36, L/M = 1.50 ± 0.14) when macrophages had been depleted in advance. After being treated with cyclophosphamide (CTX) or methotrexate (MTX), R/M and L/M decreased to 3.58 ± 0.52 and 2.03 ± 0.32 (CTX treatment) or 2.48 ± 0.64 and 1.83 ± 0.06 (MTX treatment). R/M and L/M were highly correlated with pathological changes. The trend of hydroxyproline content in lungs at the later non-inflammatory phase of each group was similar to the uptake values of the lung in the 4th week from the beginning of induction. [^99mTc]Tc-HYNFA had an ideal uptake in SSc lesions. R/M and L/M had a high consistency with pathological changes. SPECT imaging-targeted FR could monitor the therapeutic effect of CTX and MTX. It is expected to be an effective means to evaluate SSc.

Targeting the activity of T cells by membrane surface redox regulation for cancer theranostics

T cells play a determining role in the immunomodulation and prognostic evaluation of cancer treatments relying on immune activation. While specific biomarkers determine the population and distribution of T cells in tumours, the in situ activity of T cells is less studied. Here we designed T-cell-targeting fusogenic liposomes to regulate and quantify the activity of T cells by exploiting their surface redox status as a chemical target. The T-cell-targeting fusogenic liposomes equipped with 2,2,6,6-tetramethylpiperidine (TEMP) groups neutralize reactive oxygen species protecting T cells from oxidation-induced loss of activity. Meanwhile, the production of paramagnetic 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) radicals allows magnetic resonance imaging quantification of the T cell activity. In multiple mouse models, the T-cell-targeting fusogenic liposomes led to efficient tumour inhibition and to early prediction of radiotherapy outcomes. This study uses a chemical targeting strategy to measure the in situ activity of T cells for cancer theranostics and may provide further understanding on engineering T cells for cancer treatment.

[Effects of insulin glargine at different times on organ oxidative stress in burned rats with delayed resuscitation]

Objective: To examine the antioxidant effect of low dosage insulin glargine intervention at different time in rats with delayed resuscitation after burn, in order to acquire a better time of antioxidant intervention during delayed resuscitation following burn injury. Methods: With 10 rats in each group, 50 male SD rats were assigned to sham injury group, delayed resuscitation group, immediate post-burn insulin glargine treatment group (immediate treatment group), 2 hours post-burn insulin glargine treatment group(2 h treatment group), and 6 hours post-burn insulin treatment group(6 h treatment group) with random number table. Each treatment group received subcutaneous injections of insulin glargine (1.0 U·kg^-1·d^-1) immediately, two hours and six hours after the burn, while the delayed resuscitation group received the same amount of normal saline six hours after the burn. To imitate delayed fluid resuscitation, the delayed resuscitation group and each therapy group were intraperitoneally injected with normal saline (40 ml/kg) 6 hours after injury. No medicine and fluid resuscitation was administered to the sham injury group. Rats in the sham injury group had their abdominal aortic blood, hearts, and kidney tissues collected immediately after injury, while rats in the other groups had their blood and tissues collected 24 hours later. To analyze the timing of antioxidant intervention, the activities of CuZn-superoxide dismutase (CuZn-SOD), catalase (CAT), glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), xanthine oxidase (XOD) and myeloperoxidase (MPO) in blood glucose and myocardial and renal tissues were measured by spectrophotometry. Results: Compared with the sham group, blood glucose levels in the delayed resuscitation group increased [(10.72±0.80) vs (6.57±0.82)mmol/L,P<0.001], while in the myocardium and kidney, the activities of CuZn-SOD, CAT, GSH-Px and T-AOC decreased (all P<0.05) and the activities of XOD and MPO increased (all P<0.05). Compared with the delayed resuscitation group, blood glucose decreased in the immediate, 2 h, and 6 h treatment groups (all P<0.05). In the immediate and 2 h treatment group, the activities of CuZn-SOD, CAT, GSH-Px and T-AOC in the myocardium and kidney increased(all P<0.05). In the 6 h treatment group, only the activities of GSH-Px in myocardium, CAT and GSH-Px in kidney increased (all P<0.05). Compared with the delayed resuscitation group, in the immediate treatment group, the activities of MPO and XOD in myocardial tissue and XOD in renal tissue decreased (all P<0.05). The activities of MPO and XOD in myocardial and renal tissues of the 2 h treatment group both decreased (all P<0.05). In the 6 h treatment group, the activities of MPO in myocardial tissue and XOD in renal tissue both decreased (all P<0.05). Compared with the immediate treatment group, the activity of GSH-Px in myocardial tissue increased (P<0.05), and the activities of CuZn-SOD, CAT, GSH-Px and T-AOC in renal tissue increased in the 2 h treatment group (all P<0.05). The activities of CuZn-SOD, CAT, GSH-Px and T-AOC in myocardium of 6 h treatment group decreased (all P<0.05). Compared with the immediate treatment group, the activities of XOD and MPO in myocardial tissue and XOD in renal tissue of the 2 h treatment group had no significant difference (all P>0.05), but the activity of MPO in renal tissue decreased (P<0.05). The activities of XOD and MPO in myocardial tissue of the 6 h treatment group increased (all P<0.05). Compared with the 2 h treatment group, the activities of CuZn-SOD, CAT and GSH-Px and T-AOC in myocardium and kidney tissues in the 6 h treatment group decreased (all P<0.05), while the activities of XOD and MPO in myocardium and kidney tissues increased [myocardium: (374±8) vs (290±19) U/g, (0.021 8±0.003 9) vs (0.010 7±0.002 4) U/g, kidney: (157±6) vs (128±9) U/g, (0.026 8±0.004 3) vs (0.013 4±0.003 1) U/g, all P<0.05]. Conclusions: The timing of the intervention is related to the antioxidant effect of insulin glargine during delayed burn resuscitation. The intervention immediately and 2 hours after burn could have a better antioxidant effect compared to the intervention at 6 hours after burn.

Synergism of 64Cu-Labeled RGD with Anti-PD-L1 Immunotherapy for the Long-Acting Antitumor Effect

We put forward a novel targeting-triggering-therapy (TTT) scheme that combines ⁶⁴Cu-based targeted radionuclide therapy (TRT) with programmed death-ligand 1 (PD-L1)-based immunotherapy for enhancing therapeutic efficacy. The α_vβ₃ integrin-targeted ⁶⁴Cu-DOTA-EB-cRGDfK (⁶⁴Cu-DER) was synthesized. Flow cytometry, immunofluorescence staining, and RT-qPCR were performed to verify PD-L1 upregulation after irradiation with ⁶⁴Cu-DER. Positron emission tomography imaging was performed to investigate the prominent tumor retention property of ⁶⁴Cu-DER. In the MC38 tumor model, anti-PD-L1 antibody (αPD-L1 mAb) was delivered in a concurrent or sequential manner after ⁶⁴Cu-DER was injected, followed by the testing of changes in tumor microenvironment (TME). PD-L1 was upregulated in a time- and dose-dependent manner after being induced by ⁶⁴Cu-DER. The combination of ⁶⁴Cu-DER TRT (925 MBq/kg) and αPD-L1 mAb (10 mg/kg) resulted in significant delay in tumor growth and protected against tumor rechallenge. Blockade of PD-L1 at 4 h after ⁶⁴Cu-DER TRT (⁶⁴Cu-DER + αPD-L1 mAb @ 4 h combination group) was able to achieve 100% survival rate, prevent tumor relapse, and evidently prolong the survival of mice. In summary, the combination of ⁶⁴Cu-DER and αPD-L1 mAb in a time-dependent manner could be a promising approach to improve therapeutic efficacy. Understandably, this strategy has the potential to extend the scope of ⁶⁴Cu-based TTT and merits translation into clinical practice for the better management of immune checkpoint blockade immunotherapy.

Integrin binding peptides facilitate growth and interconnected vascular-like network formation of rat primary cortical vascular endothelial cells in vitro

Neovascularization and angiogenesis in the brain are important physiological processes for normal brain development and repair/regeneration following insults. Integrins are cell surface adhesion receptors mediating important function of cells such as survival, growth and development during tissue organization, differentiation and organogenesis. In this study, we used an integrin-binding array platform to identify the important types of integrins and their binding peptides that facilitate adhesion, growth, development, and vascular-like network formation of rat primary brain microvascular endothelial cells. Brain microvascular endothelial cells were isolated from rat brain on post-natal day 7. Cells were cultured in a custom-designed integrin array system containing short synthetic peptides binding to 16 types of integrins commonly expressed on cells in vertebrates. After 7 days of culture, the brain microvascular endothelial cells were processed for immunostaining with markers for endothelial cells including von Willibrand factor and platelet endothelial cell adhesion molecule. 5-Bromo-2'-dexoyuridine was added to the culture at 48 hours prior to fixation to assess cell proliferation. Among 16 integrins tested, we found that α₅β₁, α_vβ₅ and α_vβ₈ greatly promoted proliferation of endothelial cells in culture. To investigate the effect of integrin-binding peptides in promoting neovascularization and angiogenesis, the binding peptides to the above three types of integrins were immobilized to our custom-designed hydrogel in three-dimensional (3D) culture of brain microvascular endothelial cells with the addition of vascular endothelial growth factor. Following a 7-day 3D culture, the culture was fixed and processed for double labeling of phalloidin with von Willibrand factor or platelet endothelial cell adhesion molecule and assessed under confocal microscopy. In the 3D culture in hydrogels conjugated with the integrin-binding peptide, brain microvascular endothelial cells formed interconnected vascular-like network with clearly discernable lumens, which is reminiscent of brain microvascular network in vivo. With the novel integrin-binding array system, we identified the specific types of integrins on brain microvascular endothelial cells that mediate cell adhesion and growth followed by functionalizing a 3D hydrogel culture system using the binding peptides that specifically bind to the identified integrins, leading to robust growth and lumenized microvascular-like network formation of brain microvascular endothelial cells in 3D culture. This technology can be used for in vitro and in vivo vascularization of transplants or brain lesions to promote brain tissue regeneration following neurological insults.

Synthesis, preclinical evaluation and radiation dosimetry of a dual targeting PET tracer [68Ga]Ga-FAPI-RGD

To enhance tumor uptake and retention, we designed and developed bi-specific heterodimeric radiotracers targeting both FAP and αvβ3, [⁶⁸Ga]Ga-FAPI-RGD. The present study aimed to evaluate the specificity, pharmacokinetics, and dosimetry of [⁶⁸Ga]Ga-FAPI-RGD by preclinical and preliminary clinical studies.

Methods: FAPI-RGD was designed and synthesized with the quinoline-based FAPI-02 and the cyclic RGDfK peptide. Preclinical pharmacokinetics were determined in Panc02 xenograft model using microPET and biodistribution experiments. The safety and effective dosimetry of [⁶⁸Ga]Ga-FAPI-RGD was evaluated in 6 cancer patients, and compared with 2-[¹⁸F]FDG imaging.

Results: The [⁶⁸Ga]Ga-FAPI-RGD had good stability in saline for at least 4 h, and showed favorable binding affinity and specificity in vitro and in vivo. Compared to [⁶⁸Ga]Ga-FAPI-02 and [⁶⁸Ga]Ga-RGDfK, the tumor uptake and retention of [⁶⁸Ga]Ga-FAPI-RGD were very much enhanced than its monomeric counterparts at all the time points examined by microPET imaging. A total of 6 patients with various malignant tumors were prospectively enrolled. The effective dose of [⁶⁸Ga]Ga-FAPI-RGD was 1.94E-02 mSv/MBq. The biodistribution of [⁶⁸Ga]Ga-FAPI-RGD from 0 to 2 h after injection demonstrated rapid and high tumor uptake, prolonged tumor retention, and high tumor-to-background ratios (TBRs) which further increased over time. No significant difference in mean SUVmax of [⁶⁸Ga]Ga-FAPI-RGD and 2-[¹⁸F]FDG was present in primary tumors (8.9±3.2 vs. 10.3 ± 6.9; p = 0.459).

Conclusion: The dual targeting PET tracer [⁶⁸Ga]Ga-FAPI-RGD showed significantly improved tumor uptake and retention, as well as cleaner background over ⁶⁸Ga-labeled FAPI and RGD monospecific tracers. The first-in-human biodistribution study showed high TBRs over time, suggesting high diagnostic performance and favorable tracer kinetics for potential therapeutic applications.

Novel Radiolabeled TMTP1 for Long-Acting Hepatocellular Carcinoma Therapeutics

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

Toxicity Profiles and Protective Effects of Antifreeze Proteins From Insect in Mammalian Models

Antifreeze proteins (AFPs), found in many cold-adapted organisms, can protect them from cold and freezing damages and have thus been considered as additional protectants in current cold tissue preservation solutions that generally include electrolytes, osmotic agents, colloids and antioxidants, to reduce the loss of tissue viability associated with cold-preservation. Due to the lack of toxicity profile studies on AFPs, their inclusion in cold preservation solutions has been a trial-and-error process limiting the development of AFPs' application in cold preservation. To assess the feasibility of translating the technology of AFPs for mammalian cell cold or cryopreservation, we determined the toxicity profile of two highly active beetle AFPs, DAFP1 and TmAFP, from Dendroides canadensis and Tenebrio molitor in this study. Toxicity was examined on a panel of representative mammalian cell lines including testicular spermatogonial stem cells and Leydig cells, macrophages, and hepatocytes. Treatments with DAFP1 and TmAFP at up to 500μg/mL for 48 and 72hours were safe in three of the cell lines, except for a 20% decrease in spermatogonia treated with TmAFP. However, both AFPs at 500μg/mL or below reduced hepatocyte viability by 20 to 40% at 48 and 72h. At 1000μg/mL, DAFP1 and TmAFP reduced viability in most cell lines. While spermatogonia and Leydig cell functions were not affected by 1000μg/mL DAFP1, this treatment induced inflammatory responses in macrophages. Adding 1000μg/ml DAFP1 to rat kidneys stored at 4°C for 48hours protected the tissues from cold-related damage, based on tissue morphology and gene and protein expression of two markers of kidney function. However, DAFP1 and TmAFP did not prevent the adverse effects of cold on kidneys over 72hours. Overall, DAFP1 is less toxic at high dose than TmAFP, and has potential for use in tissue preservation at doses up to 500μg/mL. However, careful consideration must be taken due to the proinflammatory potential of DAFP1 on macrophages at higher doses and the heighten susceptibility of hepatocytes to both AFPs.

PD-L1-Targeted Radionuclide Therapy Combined with αPD-L1 Antibody Immunotherapy Synergistically Improves the Antitumor Effect

Immune checkpoint blockers (ICBs) targeting programmed death receptor 1 (PD-1) ligand 1 (PD-L1) for immunotherapy have radically reformed oncology. It is of great significance to enhance the response rate of ICB in cancer patients. Here, a radioiodinated anti-PD-L1 antibody (¹³¹I-αPD-L1) was developed for PD-L1-targeted single-photon emission computed tomography (SPECT) imaging and αPD-L1 immunotherapy. Flow cytometry and immunofluorescence staining were performed to identify PD-L1 upregulation in a time- and dose-dependent manner after being induced by ¹³¹I-αPD-L1. ImmunoSPECT imaging and biodistributions of ¹³¹I-αPD-L1 in CT26, MC38, 4T1, and B16F10 tumor models were conducted to visualize the high tumor uptake and low background signal. Compared to monotherapy alone, concurrent administration of αPD-L1 mAb and ¹³¹I-αPD-L1 revealed improved tumor control in murine tumor models. The combination of 11.1 MBq of ¹³¹I-αPD-L1 and 200 μg of αPD-L1 mAb resulted in significant tumor growth delay and prolonged survival. This radioligand synergized immunotherapy strategy holds great potential for cancer management.

Dual Targeting of Integrin αvβ3 and Neuropilin-1 Receptors Improves Micropositron Emission Tomography Imaging of Breast Cancer

The receptors neuropilin-1 (NRP-1) and integrin α_vβ₃ are overexpressed in breast cancer and associated with neovascularization. We synthesized a heterodimeric tracer, ⁶⁸Ga-DOTA-RGD-ATWLPPR, which simultaneously targets integrin α_vβ₃ and NRP-1 in breast cancer. In this study, we evaluated the diagnostic efficacy of ⁶⁸Ga-DOTA-RGD-ATWLPPR during micropositron emission tomography (microPET)/X-ray computed tomography (CT) imaging and gamma counting. We evaluated the receptor-binding characteristics and tumor-targeting efficacy of the tracer in vitro and in vivo. Static microPET/CT imaging and gamma counting studies showed that ⁶⁸Ga-DOTA-RGD-ATWLPPR uptake in MCF-7 tumors is higher than that of monomeric tracers. ⁶⁸Ga-DOTA-RGD-ATWLPPR uptake could be blocked with excess unlabeled RGD or ATWLPPR, demonstrating the sensitivity and specificity of the tracer. We did not observe bone tracer uptake in vivo, but the data indicated that ⁶⁸Ga-DOTA-RGD-ATWLPPR is metabolized in the kidneys and the liver uptake is low. In conclusion, ⁶⁸Ga-DOTA-RGD-ATWLPPR has improved binding affinity, targeting efficiency, and tumor retention time when compared to monomeric tracers, suggesting that it has potential as an imaging probe for breast cancer detection.

A paradigm of cancer immunotherapy based on 2-[18F]FDG and anti-PD-L1 mAb combination to enhance the anti-tumor effect

PURPOSE

Efforts have been devoted to select eligible candidates for PD-1/PD-L1 immune checkpoint blocker (ICB) immunotherapy. Here, we have a serendipitous finding of positron emitting tomography (PET) imaging tracer 2-[18F]FDG as a potential immunomodulator. Therefore, we hypothesize that 2-[18F]FDG could induce PD-L1 expression change and create an immune-favorable microenvironment for tumor immunotherapy.

EXPERIMENTAL DESIGN

We designed a series of assays to verify PD-L1 upregulation, and tested immunotherapy regimens based on 2-[18F]FDG and anti-PD-L1 mAb, as monotherapy and in combination, in fully immunocompetent mice of MC38 and CT26 models. PD-L1 expression and tumor microenvironment (TME) changes were analyzed by western blot, transcriptomics study and flow-cytometric analysis.

RESULTS

PD-L1 was upregulated in a time- and dose-dependent manner after being induced by 2-[18F]FDG. The activation of NF-κB/IRF3 pathway and STAT1/3-IRF1 pathway play crucial parts in modulating PD-L1 expression after DNA damage and repair. Improved αPD-L1 mAb utilization rate and significant tumor growth delay were observed when the personalized therapeutic alliance of 2-[18F]FDG stimulation and ICB were employed. In addition, combination of 2-[18F]FDG with αPD-L1 mAb could reprogram a TME from "cold" to "hot", to make low immunoactivity tumors sensitive to ICB therapy.

CONCLUSIONS

In summary, this promising paradigm has the potential to expand the traditional tumor theranostics. [18F]FDG-based ICB immunotherapy is highly significant in enhancing anti-tumor effect.

Variation of Serum Uric Acid Is Associated With Gut Microbiota in Patients With Diabetes Mellitus

Diabetes mellitus is a metabolic disease closely related to a disordered gut microbiome. Diabetic patients usually suffer from various metabolic disorders, such as increased serum uric acid levels. Although serum uric acid levels depend partially on intestine excretion, the relationship between uric acid and gut microbiome in diabetic patients remains unknown. We collected a total of 126 fecal samples from diabetic patients for 16S ribosomal RNA gene amplicon sequencing and recorded clinical data. We analyzed the correlation between clinical indicators and gut microbiota of diabetic patients using Spearman analysis. Since uric acid was the most prominent one, we classified diabetic patients based on their uric acid levels to find the microbiome associated with uric acid disturbance. We constructed Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway profiles using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) to identify variations between the different groups. Among all the clinical indicators, uric acid had the strongest correlation with gut microbiota. First, we divided the patients into three groups according to their uric acid levels. The two low uric acid groups were similar, while the elevated uric acid group had significant differences in gut microbiota and metabolic pathways. The elevated uric acid group had a significantly lower gut microbiota diversity. At the genus level, this group had remarkably higher Escherichia–Shigella amounts and notably lower Faecalibacterium, Oscillospiraceae_UCG−002, and Oscillospiraceae_UCG−005 amounts. The gut microbiota of the high uric acid group was predicted to be enriched in metabolism, human diseases, and lipopolysaccharide biosynthesis. Since the two low uric acid groups were similar, we regrouped and matched the abnormal uric acid patients with normal uric acid patients. The differences in gut microbiota and metabolic pathways related to nucleotide metabolism became more significant. The serum uric acid levels were associated with gut microbiome changes. This might be related to uric acid metabolism by gut microbes. Our study indicates that targeting the gut microbiome could help manage elevated uric acid levels.

Evans blue-modified radiolabeled fibroblast activation protein inhibitor as long-acting cancer therapeutics

Rationale: Fibroblast activation protein (FAP) targeted molecular imaging radiotracers have shown promising preclinical and clinical results in tumor diagnosis. However, rapid clearance and inadequate tumor retention of these molecules have hindered them for further clinical translation in cancer therapy. In this study, we aimed to develop a series of albumin binder-truncated Evans blue (EB) modified FAP targeted radiotracers, and optimize the pharmacokinetic (PK) characteristics to overcome the existing limitations in order to apply in the radionuclide therapy of cancer.

Methods: A series of compounds with the general structure of EB-FAPI-Bn were synthesized based on a FAP inhibitor (FAPI) variant (FAPI-02) and radiolabeled with ¹⁷⁷LuCl₃. To verify the binding affinity and FAP targeting specificity of these tracers in vitro, U87MG cell uptake and competition assays were performed. Preclinical PK was evaluated in U87MG tumor-bearing mice using SPECT imaging and biodistribution studies. The lead compound EB-FAPI-B1 was selected and cancer therapeutic efficacy of ¹⁷⁷Lu-EB-FAPI-B1 was assessed in U87MG tumor-bearing mice.

Results:¹⁷⁷Lu-EB-FAPI-B1, B2, B3, B4 were stable in PBS (pH 7.4) and saline for at least 24 h. EB-FAPI-B1 showed high binding affinity (IC₅₀ = 16.5 nM) to FAP in vitro, which was comparable with that of FAPI-02 (IC₅₀ = 10.9 nM). SPECT imaging and biodistribution studies of ¹⁷⁷Lu-EB-FAPI-B1, B2, B3, B4 have proved their prominently improved tumor accumulation and retention at 96 h post-injection, especially for ¹⁷⁷Lu-EB-FAPI-B1, high tumor uptake and low background signal make it the optimal compound. Compared to the saline group, noteworthy tumor growth inhibitions of ¹⁷⁷Lu-EB-FAPI-B1 have been observed after administration of different dosages.

Conclusion: In this study, several EB modified FAPI-02 related radiopharmaceuticals have been synthesized successfully and evaluated. High binding affinity and FAP targeting specificity were identified in vitro and in vivo. Remarkably enhanced tumor uptake and retention of EB-FAPI-B1 were found over the unmodified FAPI-02. ¹⁷⁷Lu-EB-FAPI-B1 showed remarkable tumor growth suppression in U87MG tumor model with negligible side effects, indicating that ¹⁷⁷Lu-EB-FAPI-B1 is promising for clinical application and transformation.

Ligand Engineering of Titanium-Oxo Nanoclusters for Cerenkov Radiation-Reinforced Photo/Chemodynamic Tumor Therapy

The therapeutic effect of general photodynamic therapy (PDT) is gravely limited by the poor penetration depth of exogenous light radiation. In recent years, Cerenkov radiation (CR) has been exploringly applied to overcome this critical defect. However, the currently reported type I photosensitizers for CR-induced PDT (CRIT) are only TiO₂ nanoparticle-based agents with numerous fatally intrinsic drawbacks. Herein, we developed NH₂-Ti₃₂O₁₆ nanocluster (NTOC)-derived ultrasmall nanophotosensitizers (NPSs, denoted as TDPs) via innovate ligand engineering. The introduced dopamine (DA) ligands not only facilitate the water solubility and photocatalytic properties of NPSs but also involve the tumor-targeting behavior through the binding affinity with DA receptors on cancer cells. Under CR irradiation, TDPs enable efficient hydroxyl radical (·OH) generation benefiting from the enhanced separation of hole (h⁺)-electron (e^-) pairs, where the h⁺ will react with H₂O to execute type I PDT and the transferred e^- can realize the augmentation of Ti³⁺ to substantially promote the therapeutic index of chemodynamic therapy. This study provides an easy but feasible strategy for constructing versatile NPSs with an ultrasmall framework structure, propounding a refreshing paradigm for implementing efficient CR-induced combined therapy (CRICT) and spurring the development of CR and titanium-familial nanoplatforms in the fields of photocatalysis and nanocatalytic medicine.