STING-targeted PET tracer for early assessment of tumor immunogenicity in colorectal cancer after chemotherapy.

PURPOSE: To optimize chemotherapy regimens and improve the effectiveness of chemotherapy combined with immunotherapy, a PET tracer specifically targeting the stimulator of interferon genes (STING), denoted as [18F]FBTA was used to monitor the early changes in tumor immunogenicity after chemotherapy in colorectal cancer (CRC) mice. METHODS: The toluene sulfonate precursor was labeled with 18F to produce the STING targeted probe-[18F]FBTA. [18F]FBTA-PET imaging and biodistribution were performed using CRC mice treated with oxaliplatin (OXA) or cisplatin (CDDP). CRC mice were also treated with low (CDDP-LD: 1 mg/kg) or medium (CDDP-MD: 2.5 mg/kg) doses of CDDP, and subjected to PET imaging and biodistribution. The effects of different chemotherapeutic agents and different doses of CDDP on tumor innate immunity were verified by flow cytometry and immunohistochemistry. RESULTS: PET imaging of CRC mice exhibited notably enhanced tumor uptake in the early phase of chemotherapy with treatment with OXA (3.09 ± 0.25%ID/g) and CDDP (4.01 ± 0.18%ID/g), especially in the CDDP group. The PET-derived tumor uptake values have strong correlations with STING immunohistochemical score. Flow cytometry showed both agents led to DCs and macrophages infiltration in tumors. Compared with OXA, CDDP treatment recruits more DCs and macrophages in CRC tumors. Both CDDP-LD and CDDP-MD treatment elevated uptake in CRC tumors, especially in CDDP-MD group. Immunohistochemistry and flow cytometry confirmed CDDP-MD treatment recruits more DCs and macrophages than CDDP-LD treatment. CONCLUSION: Overall, the STING-targeted tracer-[18F]FBTA was demonstrated to monitor early changes in tumor immunogenicity in CRC mice after chemotherapy. Besides, the STING-targeted strategy may help to select the appropriate chemotherapy regimen, including chemotherapeutic agents and doses, which further improve clinical decision making for combination immunotherapy after chemotherapy for CRC.

Structural characterization of protein-material interfacial interactions using lysine reactivity profiling-mass spectrometry.

Understanding how proteins and materials interact is useful for evaluating the safety of biomedical micro/nanomaterials, toxicity estimation and design of nano-drugs and catalytic activity improvement of bio-inorganic functional hybrids. However, characterizing the interfacial molecular details of protein-micro/nanomaterial hybrids remains a great challenge. This protocol describes the lysine reactivity profiling-mass spectrometry strategy for determining which parts of a protein are interacting with the micro/nanomaterials. Lysine residues occur frequently on hydrophilic protein surfaces, and their reactivity is dependent on the accessibility of their amine groups. The accessibility of a lysine residue is lower when it is in contact with another object; allosteric effects resulting from this interaction might reduce or increase the reactivity of remote lysine residues. Lysine reactivity is therefore a useful indicator of protein localization orientation, interaction sequence regions, binding sites and modulated protein structures in the protein-material hybrids. We describe the optimized two-step isotope dimethyl labeling strategy for protein-material hybrids under their native and denaturing conditions in sequence. The comparative quantification results of lysine reactivity are only dependent on the native microenvironments of lysine local structures. We also highlight other critical steps including protein digestion, elution from materials, data processing and interfacial structure analysis. The two-step isotope labeling steps need ~5 h, and the whole protocol including digestion, liquid chromatography-tandem mass spectrometry, data processing and structure analysis needs ~3-5 d.

Integrated mass spectrometry strategy for functional protein complex discovery and structural characterization.

The discovery of functional protein complex and the interrogation of the complex structure-function relationship (SFR) play crucial roles in the understanding and intervention of biological processes. Affinity purification-mass spectrometry (AP-MS) has been proved as a powerful tool in the discovery of protein complexes. However, validation of these novel protein complexes as well as elucidation of their molecular interaction mechanisms are still challenging. Recently, native top-down MS (nTDMS) is rapidly developed for the structural analysis of protein complexes. In this review, we discuss the integration of AP-MS and nTDMS in the discovery and structural characterization of functional protein complexes. Further, we think the emerging artificial intelligence (AI)-based protein structure prediction is highly complementary to nTDMS and can promote each other. We expect the hybridization of integrated structural MS with AI prediction to be a powerful workflow in the discovery and SFR investigation of functional protein complexes.

Preoperative prediction of overt hepatic encephalopathy caused by transjugular intrahepatic portosystemic shunt.

PURPOSE: Preoperative prediction of overt hepatic encephalopathy (OHE) should be performed in patients with variceal bleeding treated using the transjugular intrahepatic portosystemic shunt (TIPS) procedure. A reliable prediction tool is therefore required. METHOD: Patients with cirrhosis-related variceal bleeding treated using the TIPS procedure were screened at two hospitals. Patients classified as Child-Pugh Class B were identified. The least absolute shrinkage and selection operator method and the backward stepwise selection method were used to screen the clinical and radiological characteristics of participants. Then, models were constructed accordingly to predict OHE. Area under the receiver operating characteristic curves, calibration curves, and decision curves were performed to discover the optimal model. Finally, whether clinical factors influenced the performance of our optimal model was tested. RESULTS: A total of 191 patients were included (training cohort: 127 cases; validation cohort: 64 cases). Three novel radiological independent risk factors were found. The combined model outperformed the models containing clinical factors or radiological characteristics alone. The areas under the curve for the training and validation cohorts were 0.901 and 0.903, respectively, with satisfactory calibration and decision curves. The Model for End-Stage Liver Disease score, serum sodium, albumin, total bilirubin, and age exhibited limited influence on the performance of the combined model. CONCLUSIONS: These radiological characteristics are also independent risk factors for post-TIPS OHE. Combining clinical factors and radiological characteristics was an effective means of predicting OHE. This study's model could be used for preoperative selection of appropriate patients before the TIPS procedure is performed.

Lysine reactivity profiling reveals molecular insights into human serum albumin-small-molecule drug interactions.

Human serum albumin (HSA) is one of the most important serum carrier proteins that deliver small-molecule drugs to their specific targets. Clarifying the molecular mechanism of the interaction between natural HSA and drugs in an aqueous solution has been a hot topic in pharmaceutical chemistry, clinical medicine, and biochemistry in recent years, but it is still challenging. In this paper, the details of molecular interactions of HSA with a variety of therapeutic drugs including ibuprofen, indomethacin, phenylbutazone, and warfarin are systematically investigated using a mass spectrometry (MS)-based lysine reactivity profiling (LRP) strategy. The results reaffirm that the major ligand binding sites (including Sites I and II) of HSA are located in subdomains IIA and IIIA, while several potential drug-binding areas at subdomain IIIB and α helix IIB-IIIA are newly characterized. The MS-LRP strategy may have important application prospects in pharmacodynamics, pharmacokinetics, and safety evaluation of small-molecule drugs.

Prediction of overt hepatic encephalopathy after transjugular intrahepatic portosystemic shunt treatment: a cohort study.

BACKGROUND/PURPOSE: Overt hepatic encephalopathy (HE) risk should be preoperatively predicted to identify patients suitable for curative transjugular intrahepatic portosystemic shunt (TIPS) instead of palliative treatments. METHODS: A total of 185 patients who underwent TIPS procedure were randomised (130 in the training dataset and 55 in the validation dataset). Clinical factors and imaging characteristics were assessed. Three different models were established by logistic regression analyses based on clinical factors (ModelC), imaging characteristics (ModelI), and a combination of both (ModelCI). Their discrimination, calibration, and decision curves were compared, to identify the best model. Subgroup analysis was performed for the best model. RESULTS: ModelCI, which contained two clinical factors and two imaging characteristics, was identified as the best model. The areas under the curve of ModelC, ModelI, and ModelCI were 0.870, 0.963, and 0.978 for the training dataset and 0.831, 0.971, and 0.969 for the validation dataset. The combined model outperformed the clinical and imaging models in terms of calibration and decision curves. The performance of ModelCI was not influenced by total bilirubin, Child-Pugh stages, model of end-stage liver disease score, or ammonia. The subgroup with a risk score ≥ 0.88 exhibited a higher proportion of overt HE (training dataset: 13.3% vs. 97.4%, p < 0.001; validation dataset: 0.0% vs. 87.5%, p < 0.001). CONCLUSION: Our combination model can successfully predict the risk of overt HE post-TIPS. For the low-risk subgroup, TIPS can be performed safely; however, for the high-risk subgroup, it should be considered more carefully.

18F-FDG PET/CT for Prognostic Stratification of Patients With Extranodal Natural Killer/T-Cell Lymphoma.

PURPOSE: The prognostic value of PET/CT for extranodal natural killer/T-cell lymphoma (ENKTL) patients is controversial. We sought to investigate the use of pretreatment and interim PET/CT in this disease. METHODS: Sixty-five patients diagnosed with ENKTL who underwent pretreatment (n = 53) and/or interim PET/CT scans (after 2-4 cycles of chemotherapy and/or radiotherapy, n = 33) were retrospectively enrolled. Interim PET/CT images were interpreted according to the Deauville 5-point scale. PET/CT results were assessed for their predictive value of progression-free survival (PFS) and overall survival (OS). Kaplan-Meier estimates were generated to evaluate the predictive value of clinical parameters and PET/CT scans for prognosis evaluation. The Cox proportional hazards model was performed to assess the potential independent predictors for PFS and OS. RESULTS: Patients with a high score (4/5) according to the Deauville scale had heavier tumor burdens and tended to have elevated serum LDH and ß2-microglobulin (ß2-MG). In univariate analysis, the following parameters were predictive of PFS: age (≤60 vs > 60 years), stage (I/II vs III/IV), lesion location (nasal vs extranasal), LDH (normal vs elevated), ß2-MG (normal vs elevated), SUVmax before treatment (≤8.3 vs > 8.3), and interim PET/CT results. For OS, the predictive factors were composed of stage, lesion location, LDH, ß2-MG, and interim PET/CT results. However, in multivariate analysis, only interim PET/CT scan interpreted by the Deauville scale remained as an independent predictor for both PFS and OS. CONCLUSIONS: Interim PET/CT scan displayed potential predictive value for ENKTL patients. Response assessment according to the Deauville 5-point scale may help to improve the accuracy of prediction. Patients with advanced stage (III/IV), elevated LDH or ß2-MG, and a high Deauville score of 4 to 5 on the interim PET/CT scan were more likely to have reduced PFS and OS.

Design and evaluation of a compound acoustic lens for photoacoustic computed tomography.

In photoacoustic computed tomography, the limited directivity of the detectors may cause deformation of off-center targets and lead to an imbalanced resolution in the imaging area. To improve the directivity of the acoustic detectors, several negative acoustic lenses have been proposed. In this study, we develop a new compound acoustic lens fabricated by integrating a concave polydimethylsiloxane (PDMS) lens and a convex epoxy lens. Both theoretical simulations and experimental evaluations demonstrate that the compound lens provides a larger directivity compared to single lenses made of PDMS, epoxy, and liquid. The measured acceptance angles of a 6-mm piezoelectric acoustic transducer equipped with the compound, epoxy, liquid, and PDMS lenses are 55°, 36°, 25°, and 20°, respectively. No deformation is observed in the off-center targets by using compound lens. However, serious deformation appears in the cases using single lenses.

Localization and characterization of rat transmembrane protein 225 specifically expressed in testis.

Testis is the one and only location of spermatogenesis and sexual hormone production. Spermatogenesis is a complicated physiological process regulated by many genes specifically and differentially expressed in the testis. In this study, Transmembrane Protein 225 (TMEM225), which is specifically expressed in rat testis, has been identified. TMEM225 was cloned from the testis cDNA library and was mapped to chromosome 8q22 by browsing the University of California Santa Cruz genomic database. It contains an open reading frame with a length of 696 bp, encoding a protein with four putative transmembrane helices. TMEM225 mRNA expression was evaluated by reverse transcription-polymerase chain reaction and in situ hybridization. In addition, the subcellular location of TMEM225 was evaluated. The results obtained highlighted age related specific expression of TMEM225 in testis, specifically during the adult period after age of 13 months. In situ hybridization analysis indicated that TMEM225 mRNA was mainly expressed in spermatocyte cells and round spermatids. Green fluorescence protein localization analysis showed that rat TMEM225 mainly surrounded the nuclear membrane, with a minority distribution in the cytoplasm, and the distribution of TMEM225 was affected by the deletion of N-terminal transmembrane domain. As the expression phase is not related to the first wave of spermatozoon development, our data presented here suggest that TMEM225 may play an important role in sperm degeneration but not in spermatogenesis.