A dual-labeling fluorescent probe to track lysosomal polarity and endoplasmic reticulum dynamics during ferroptosis.

A polarity-sensitive probe was developed to simultaneously label lysosomes and endoplasmic reticulum (ER) via its dansylamide and rhodamine fluorescence, respectively, enabling ratiometric polarity detection and stable dual-labeling. The fragmented ER network and increased lysosomal polarity during ferroptosis were revealed, which facilitates the understanding of ferroptotic mechanisms.

Predicting human epidermal growth factor receptor 2 status of patients with gastric cancer by computed tomography and clinical features.

Background: There have been no studies on predicting human epidermal growth factor receptor 2 (HER2) status in patients with resectable gastric cancer (GC) in the neoadjuvant and perioperative settings. We aimed to investigate the use of preoperative contrast-enhanced computed tomography (CECT) imaging features combined with clinical characteristics for predicting HER2 expression in GC. Methods: We retrospectively enrolled 301 patients with GC who underwent curative resection and preoperative CECT. HER2 status was confirmed by postoperative immunohistochemical analysis with or without fluorescence in situ hybridization. A prediction model was developed using CECT imaging features and clinical characteristics that were independently associated with HER2 status using multivariate logistic regression analysis. Receiver operating characteristic curves were constructed and the performance of the prediction model was evaluated. The bootstrap method was used for internal validation. Results: Three CECT imaging features and one serum tumor marker were independently associated with HER2 status in GC: enhancement ratio in the arterial phase (odds ratio [OR] = 4.535; 95% confidence interval [CI], 2.220-9.264), intratumoral necrosis (OR = 2.64; 95% CI, 1.180-5.258), tumor margin (OR = 3.773; 95% CI, 1.968-7.235), and cancer antigen 125 (CA125) level (OR = 5.551; 95% CI, 1.361-22.651). A prediction model derived from these variables showed an area under the receiver operating characteristic curve of 0.802 (95% CI, 0.740-0.864) for predicting HER2 status in GC. The established model was stable, and the parameters were accurately estimated. Conclusions: Enhancement ratio in the arterial phase, intratumoral necrosis, tumor margin, and CA125 levels were independently associated with HER2 status in GC. The prediction model derived from these factors may be used preoperatively to estimate HER2 status in GC and guide clinical treatment.

Synthesis, Screening, and Evaluation of Theranostic Molecular CPCR4-Based Probe Targeting CXCR4.

Chemokines and chemokine receptors are indispensable to play a key role in the development of malignant tumors. As one of the most widely expressed chemokine receptors, chemokine (C-X-C motif) receptor 4 (CXCR4) has been a popular research focus. In most tumors, CXCR4 expression is significantly upregulated. Moreover, integrated nuclide diagnosis and therapy targeting CXCR4 show great potential. [68Ga]Ga-pentixafor, a radioligand targeting CXCR4, exhibits a strong affinity for CXCR4 both in vivo and in vitro. However, [177Lu]Lu-pentixather, the therapeutic companion of [68Ga]Ga-pentixafor, requires significant refinement to mitigate its pronounced hepatic biodistribution. The objective of this study was to synthesize theranostic molecular tracers with superior CXCR4 targeting functions. The Daudi cell line, which highly expressed CXCR4, and the MM.1S cell line, which weakly expressed CXCR4, were used in this study. Based on the pharmacophore cyclo (-d-Tyr-n-me-d-Orn-l-Arg-L-2-NAL-Gly-) (CPCR4) of pentixafor, six tracers were synthesized: [124I]I-1 ([124I]I-CPCR4), [99mTc]Tc-2 ([99mTc]Tc-HYNIC-CPCR4), [124I]I-3 ([124I]I-pentixafor), [18F]AlF-4 ([18F]AlF-NETA-CPCR4), [99mTc]Tc-5 ([99mTc]Tc-MAG3-CPCR4) and [124I]I-6 ([124I]I-pentixafor-Ga) and their radiochemical purities were all higher than 95%. After positron emission tomography (PET)/single-photon emission computed tomography (SPECT) imaging, the [124I]I-6 group exhibited the best target-nontarget ratio. At the same time, comparing the [68Ga]Ga-pentixafor group with the [124I]I-6 group, we found that the [124I]I-6 group had a better target-nontarget ratio and lower uptake in nontarget organs. Therefore, compound 6 was selected for therapeutic radionuclide (131I) labeling, and the tumor-bearing animal models were treated with [131I]I-6. The volume of the tumor site was significantly reduced in the treatment group compared with the control group, and no significant side effects were found. [124I]I-6 and [131I]I-6 showed excellent affinity for targeting CXCR4, and they showed great potential for the integrated diagnosis and treatment of tumors with high CXCR4 expression.

Preclinical Evaluation of 99mTc-MAG3-5-Fab Targeting TREM2 in Lung Cancer Mouse Models: A Comparison with 99mTc-MAG3-5-F(ab')2.

Triggering receptor expressed on myeloid cells-2 (TREM2), which is expressed on the surface of tumor-associated macrophages (TAMs), has been found to play a major role in the diagnosis and treatment of tumors. TREM2 expression is significantly upregulated in tumor tissues, and therefore, targeting TREM2 for tumor imaging may be of value. Previously, we performed TREM2 targeting imaging by using 68Ga-NOTA-COG1410 or a 124I-labeled monoclonal antibody (mAb) and F(ab')2 in mouse models of colon and gastric tumors. However, some of the shortcomings of these probes (i.e., the high uptake of 68Ga-NOTA-COG1410 in the liver, the difficulty of obtaining iodine-124, and the long half-life of iodine-124) have hindered their clinical use. Herein, we sought to synthesize novel molecular probes targeting TREM2 that are more conducive to clinical translation, eliminating the interference of isotope availability and in vivo probe biodistribution issues. Therefore, we established A549 cell lines with negative human TREM2 (hTREM2) expression (GFP tag; hTREM2- A549) or upregulated hTREM2 expression (GFP tag; hTREM2+ A549) using lentiviral transfection and confirmed these with Western blotting and immunocytochemistry. We then prepared a mouse anti-human TREM2 (5-mAb) by immunizing with the hTREM2 antigen. The antibody fragments 5-F(ab')2 and 5-Fab were prepared from 5-mAb, and 99mTc-MAG3-5-F(ab')2 and 99mTc-MAG3-5-Fab were then synthesized with excellent stability and specificity. 99mTc-MAG3-5-F(ab')2 had a slightly higher in vitro affinity than 99mTc-MAG3-5-Fab (Kd = 3.32 ± 0.05 nmol versus 4.62 ± 0.85 nmol). 99mTc-MAG3-5-F(ab')2 and 99mTc-MAG3-5-Fab both showed excellent specificity: after adding a 100-fold precursor, the two probes binding to the cells were almost blocked. In vivo pharmacokinetics showed that the distribution and elimination half-lives of 99mTc-MAG3-5-Fab (T1/2α = 1.25 ± 0.30 min and T1/2ß = 21.98 ± 2.80 min, respectively) were significantly reduced compared to those of 99mTc-MAG3-5-F(ab')2 (T1/2α = 2.64 ± 0.37 min and T1/2ß = 86.55 ± 26.86 min, respectively). In micro single-photon emission computed tomography/computed tomography (micro-SPECT/CT) imaging, the tumor was clearly displayed at 1 h after 99mTc-MAG3-5-Fab injection, while the blood background was extremely low at 3 h, and the probe was mainly excreted through the kidneys and biliary tract. 99mTc-MAG3-5-F(ab')2 uptake was also detected at the tumor site, although the blood background was consistently high. The biodistribution results were consistent with the micro-SPECT/CT imaging results. 99mTc-MAG3-5-Fab could clearly display hTREM2+ A549 tumors in a short time (1 h) with low uptake in nontumor organs and tissues and thus has clinical application prospects.

SMURF2 predisposes cancer cell toward ferroptosis in GPX4-independent manners by promoting GSTP1 degradation.

Ferroptosis is a non-apoptotic form of regulated cell death. Glutathione (GSH) peroxidase 4 (GPX4) and GSH-independent ferroptosis suppressor protein 1 (FSP1) have been identified as major defenses. Here, we uncover a protective mechanism mediated by GSH S-transferase P1 (GSTP1) by monitoring proteinomic dynamics during ferroptosis. Dramatic downregulation of GSTP1 is caused by SMURF2-mediated GSTP1 ubiquitination and degradation at early stages of ferroptosis. Intriguingly, GSTP1 acts in GPX4- and FSP1-independent manners by catalyzing GSH conjugation of 4-hydroxynonenal and detoxifying lipid hydroperoxides via selenium-independent GSH peroxidase activity. Genetic modulation of the SMURF2/GSTP1 axis or the pharmacological inhibition of GSTP1's catalytic activity sensitized tumor responses to Food and Drug Administration (FDA)-approved ferroptosis-inducing drugs both in vitro and in vivo. GSTP1 expression also confers resistance to immune checkpoint inhibitors by blunting ferroptosis. Collectively, these findings demonstrate a GPX4/FSP1-independent cellular defense mechanism against ferroptosis and suggest that targeting SMURF2/GSTP1 to sensitize cancer cells to ferroptosis has potential as an anticancer therapy.

The opportunities and challenges in immunotherapy: Insights from the regulation of PD-L1 in cancer cells.

The immunosuppressive molecule programmed death-ligand 1 (PD-L1) is frequently upregulated in human cancers. Binding of PD-L1 to its receptor, programmed death-1 (PD-1), on activated T cells facilitates cancer cells to evade the host immune system. Antibody-based PD-1/PD-L1 inhibitors can inhibit PD-1/PD-L1 interaction allowing reactivate cytotoxic T cells to eradicate advanced cancer cells. However, the majority of cancer patients fail to respond to anti-PD-1/PD-L1 therapies and the molecular mechanisms for this remain poorly understood. Recent studies show that PD-L1 expression level on tumor cells affect the clinical efficacy of immune checkpoint therapies. Thus, furthering our understanding of the regulatory mechanisms of PD-L1 expression in cancer cells will be critical to improve clinical response rates and the efficacy of PD-1/PD-L1 immune therapies. Here we review recent studies, primarily focusing on the mechanisms that regulate PD-L1 expression at the transcriptional, post-transcriptional and protein level, with the purpose to drive the development of more targeted and effective anti-PD-1/PD-L1 cancer therapies.

Optimization of machine learning classification models for tumor cells based on cell elements heterogeneity with laser-induced breakdown spectroscopy.

The rapid and accurate diagnosis of cancer is an important topic in clinical medicine. In the present work, an innovative method based on laser-induced breakdown spectroscopy (LIBS) combined with machine learning was developed to distinguish and classify different tumor cell lines. The LIBS spectra of cells were first acquired. Then the spectral pre-processing was performed as well as detailed optimization to improve the classification accuracy. After that, the convolutional neural network (CNN), support vector machine (SVM), and K-nearest neighbors were further compared for the optimized classification ability of tumor cells. Both the CNN algorithm and SVM algorithm have achieved impressive discrimination performances for tumor cells distinguishing, with an accuracy of 97.72%. The results show that the heterogeneity of elements in tumor cells plays an important role in distinguishing the cells. It also means that the LIBS technique can be used as a fast classification method for classifying tumor cells.

Long noncoding RNA HITT coordinates with RGS2 to inhibit PD-L1 translation in T cell immunity.

Programmed cell death ligand 1 (PD-L1) is an immune checkpoint protein frequently expressed in human cancers that contributes to immune evasion through its binding to PD-1 on activated T cells. Unveiling the mechanisms underlying PD-L1 expression is essential for understanding the impact of the immunosuppressive microenvironment and is also crucial for the purpose of reboosting antitumor immunity. However, how PD-L1 is regulated, particularly at translational levels, remains largely unknown. Here, we discovered that a long noncoding RNA (lncRNA), HIF-1α inhibitor at translation level (HITT), was transactivated by E2F transcription factor 1 (E2F1) under IFN-γ stimulation. It coordinated with regulator of G protein signaling 2 (RGS2) in binding to the 5' UTR of PD-L1, resulting in reduced PD-L1 translation. HITT expression enhanced T cell-mediated cytotoxicity both in vitro and in vivo in a PD-L1-dependent manner. The clinical correlation between HITT/PD-L1 and RGS2/PD-L1 expression was also detected in breast cancer tissues. Together, these findings demonstrate the role of HITT in antitumor T cell immunity, highlighting activation of HITT as a potential therapeutic strategy for enhancing cancer immunotherapy.

124I-Labeled Immuno-PET Targeting hTREM2 for the Diagnosis of Gastric Carcinoma.

Low ß-2-[18F]-fluoro-2-deoxy-d-glucose (18F-FDG) uptake in gastric mucinous adenocarcinoma may cause false-negative diagnosis and erroneous staging. Thus, there is an urgent need for developing tumor-specific imaging agents in gastric cancer diagnostics. Triggering receptor expressed on myeloid cells 2 (TREM2) is a transmembrane protein expressed on the surface of tumor-associated macrophages (TAMs) and is considerably overexpressed in tumor tissues. This study aimed to develop new human TREM2 (hTREM2)-targeting imaging agents to diagnose and monitor gastric cancer. We established a cell line, MGC803, with upregulated expression of hTREM2, at the cell surface. We produced a monoclonal antibody (5-mAb) against hTREM2 by immunizing mice with the hTREM2 antigen to obtain the antibody fragment 5-F(ab')2 using an immunoglobulin G-degrading enzyme of Streptococcus pyogenes (IdeS). Another anti-TREM2-mAb (clone 237920) and its fragment anti-TREM2-F(ab')2 were employed for the comparative study in vitro and in vivo. After 124I labeling, we constructed the probes: 124I-5-mAb, 124I-5-F(ab')2, 124I-anti-TREM2-mAb, and 124I-anti-TREM2-F(ab')2. We found that 5-mAb exhibited higher hTREM2 affinity and slower blood clearance than anti-TREM2-mAb, whose corresponding F(ab')2 fragments demonstrated the same trend. The micro-PET/CT revealed that 124I-5-F(ab')2 exhibited advantages of tumor enrichment and fast metabolism. The biodistribution study results were consistent with those of micro-PET/CT. Among the four tracers, 124I-5-F(ab')2 was the most suitable specific radiotracer for targeting hTREM2 and displayed potential utility as a tumor-imaging tracer for diagnosing gastric carcinoma.

Noninvasive evaluation of PD-L1 expression in non-small cell lung cancer by immunoPET imaging using an acylating agent-modified antibody fragment.

PURPOSE: The aim of this study was to explore an effective 124I labeling strategy and improve the signal-to-noise ratio when evaluating the expression of PD-L1 using an 124I-iodinated durvalumab (durva) F(ab')2 fragment. METHODS: The prepared durva F(ab')2 fragments were incubated with N-succinimidyl-3-(4-hydroxyphenyl) propionate (SHPP); after purification, the HPP-durva F(ab')2 was iodinated using Iodo-Gen method. After the radiochemical purity, stability, and specific activities were determined, the binding affinities of probes prepared using different labeling strategies were compared in vitro. The clinical application value of [124I]I-HPP-durva-F(ab')2 was confirmed by PET imaging. To more objectively evaluate the in vivo distribution and clearance of tracers, the pharmacokinetics and biodistribution assays were also performed. RESULTS: After being modified with SHPP, the average conjugation number of SHPP per durva-F(ab')2 identified by LC-MS was about 8.92 ± 2.84. The prepared [124I]I-HPP-durva F(ab')2 was obtained with a satisfactory radiochemical purity of more than 98% and stability of more than 93% when incubated for 72 h. Compared with unmodified [124I]I-durva F(ab')2, the specific activity of [124I]I-HPP-durva-F(ab')2 was improved (52.91 ± 5.55 MBq/mg and 15.91 ± 0.74 MBq/mg), while the affinity did not significantly change. The biodistribution experiments and PET imaging showed that the prepared [124I]I-HPP-durva-F(ab')2 exhibited an accelerated clearance and improved tumor-to-background ratio compared with [124I]I-durva-F(ab')2. The specificity of [124I]I-HPP-durva-F(ab')2 to PD-L1 was well demonstrated both in vitro and in vivo. CONCLUSIONS: A PD-L1 PET imaging probe [124I]I-HPP-durva F(ab')2 was successfully synthesized through the SHPP modification strategy. The prepared probe was able to accurately evaluate the PD-L1 expression level through high-contrast noninvasive imaging.

Efficacy and Prognostic Factors of Immune Checkpoint Inhibitors in the Treatment of Advanced Non-small Cell Lung Cancer.

OBJECTIVE: To discuss the efficacy and potential prognostic factors of immune checkpoint inhibitors (ICIs) in patients with advanced non-small cell lung cancer (NSCLC). METHODS: A retrospective study was conducted to analyze the medical history of patients (n=111) confirmed with advanced NSCLC in the Affiliated Hospital of Putian University from 2018 to 2020. All enrolled patients with adenocarcinoma (n=69), squamous cell carcinoma (n=28), and other types of lung cancer (n=14) were treated with the programmed death-ligand 1 (PD-1) inhibitors. They were divided into groups of PD-1 inhibitors, PD-1 inhibitors in combination with chemotherapy, and PD-1 inhibitors in combination with chemotherapy and angiogenesis inhibitors according to the treatment regimen. General clinical data of all patients were collected, and the Kaplan-Meier analysis was applied to estimate progression-free survival (PFS) and overall survival (OS). In addition, univariate and multivariate Cox regression analyses were performed to analyze prognostic factors associated with PFS and OS after treatment. RESULTS: Of 111 patients with advanced NSCLC treated with ICIs, 6 were fully responsive, 33 were partially responsive, 55 were stable, and 17 were progressive. There was no significant difference in objective response rate between the 3 groups. In the subgroup analysis according to the lines of therapy, the objective response rate of patients receiving first-line treatment was 46.7%, which was significantly higher than that of other line treatment groups ( P =0.014). The results of multivariate Cox regression analysis indicated that the history of hormone use (HR=1.593; P =0.033), second-line or further lines of therapy (HR=2.871; P <0.001), and high neutrophil/lymphocyte ratio (NLR; HR=1.498; P =0.045) were independent risk factors for PFS after immunotherapy for advanced NSCLC. And the history of hormone use (HR=1.518; P =0.015) and high NLR (HR=3.053; P =0.001) were as well the independent risk factors for OS after immunotherapy for advanced NSCLC. CONCLUSION: ICIs therapy clearly had a greater survival benefit in patients who received first-line therapy, had no history of hormone use, and showed low NLR after initial treatment. ICIs can be an effective treatment for advanced NSCLC.

Dynamic Total-Body PET/CT Imaging Reveals Kinetic Distribution of 68Ga-DOTATATE in Normal Organs.

Objective: To investigate the biodistribution and kinetic constants of 68Ga-DOTATATE in normal organs through dynamic total-body positron emission tomography/computed tomography (PET/CT). Methods: Seven patients who experienced endoscopic resection of gastric neuroendocrine tumor were enrolled. Dynamic total-body PET/CT scans over 60 min were performed. Time-activity curves were obtained by drawing regions of interest in normal organs. Rate constants, including K 1, k 2, k 3, and vB, were computed using a two-tissue compartment model. Factor analysis was used to compare the rate constants among subjects and regions. Hierarchical cluster analysis was performed to identify organs with similar kinetic characteristics. Results: The highest uptake of 68Ga-DOTATATE was observed in the spleen followed by kidneys, adrenals, liver, pituitary gland, pancreas head, prostate, pancreas body, and thyroid, parotid, and submandibular glands. Low background level of 68Ga-DOTATATE uptake was observed in the nasal mucosa, bone, blood pool, and cerebrum. In addition, the uptake in the pancreas head was noted to be higher than the pancreas body (P < 0.001) on the basis of each time point of dynamic PET. There were differences of rate constants among different organs. The mean K 1 ranged from 0.0507 min-1 in the left nasal mucosa to 1.21 min-1 in the left kidney, and mean k 2 ranged from 0.0174 min-1 in the spleen to 4.4487 min-1 in the left cerebrum. The mean k 3 ranged from 0.0563 min-1 in the right cerebrum to 4.6309 min-1 in the left adrenal, and mean vB ranged from 0.0001 in the left cerebrum to 0.2489 in the right adrenal. However, none of the rate constants was significantly different among subjects or among different sites within a single organ. Three groups of organs with similar kinetic characteristics were identified: (1) cerebrum; (2) pituitary gland, liver, adrenal, and prostate; and (3) nasal mucosa, parotid and submandibular glands, thyroid, spleen, pancreas, kidney, and bone. Conclusion: Uptake and clearance of 68Ga-DOTATATE, in terms of kinetic constants, were different in different organs. The kinetic parameters of 68Ga-DOTATATE in different organs provide a reference for future dynamic PET imaging.

Mitochondria-localized lncRNA HITT inhibits fusion by attenuating formation of mitofusin-2 homotypic or heterotypic complexes.

Long noncoding RNAs (lncRNAs) are emerging as essential players in multiple biological processes. Mitochondrial dynamics, comprising the continuous cycle of fission and fusion, are required for healthy mitochondria that function properly. Despite long-term recognition of its significance in cell-fate control, the mechanism underlying mitochondrial fusion is not completely understood, particularly regarding the involvement of lncRNAs. Here, we show that the lncRNA HITT (HIF-1α inhibitor at translation level) can specifically localize in mitochondria. Cells expressing higher levels of HITT contain fragmented mitochondria. Conversely, we show that HITT knockdown cells have more tubular mitochondria than is present in control cells. Mechanistically, we demonstrate HITT directly binds mitofusin-2 (MFN2), a core component that mediates mitochondrial outer membrane fusion, by the in vitro RNA pull-down and UV-cross-linking RNA-IP assays. In doing so, we found HITT disturbs MFN2 homotypic or heterotypic complex formation, attenuating mitochondrial fusion. Under stress conditions, such as ultraviolet radiation, we in addition show HITT stability increases as a consequence of MiR-205 downregulation, inhibiting MFN2-mediated fusion and leading to apoptosis. Overall, our data provide significant insights into the roles of organelle (mitochondria)-specific resident lncRNAs in regulating mitochondrial fusion and also reveal how such a mechanism controls cellular sensitivity to UV radiation-induced apoptosis.

iASPP suppression mediates terminal UPR and improves BRAF-inhibitor sensitivity of colon cancers.

Unfolded protein response (UPR) signaling is activated under endoplasmic reticulum (ER) stress, an emerging cancer hallmark, leading to either adaptive survival or cell death, while the mechanisms underlying adaptation-death switch remain poorly understood. Here, we examined whether oncogene iASPP regulates the switch and how the mechanisms can be used in colon cancer treatment. iASPP is downregulated when cells undergo transition from adaptation to death during therapy-induced ER stress. Blocking iASPP's downregulation attenuates stress-induced cell death. Mechanistically, Hu-antigen R (HuR)-mediated stabilization of iASPP mRNA and subsequent iASPP protein production is significantly impaired with prolonged ER stress, which facilitates the degradation of GRP78, a key regulator of the UPR, in the cytosol. Because iASPP competes with GRP78 in binding the ER-resident E3 ligase RNF185, and tips the balance in favor of cell death. Positive correlation between the levels of HuR, iASPP, and GRP78 are detectable in colon cancer tissues in vivo. Genetic inhibition of iASPP/GRP78 or chemical inhibition of HuR not only inhibits tumor growth, but also sensitizes colon cancer cells' responses to BRAF inhibitor-induced ER stress and cell death. This study provides mechanistic insights into the switch between adaptation and death during ER stress, and also identifies a potential strategy to improve BRAF-inhibitor efficiency in colon cancers.

Longitudinal Positron Emission Tomography Imaging with P2X7 Receptor-Specific Radioligand 18F-FTTM in a Kainic Acid Rat Model of Temporal Lobe Epilepsy.

P2X7 receptors (P2X7R), as a brain inflammation biomarker, play important roles in the epileptogenic progress. Mounting evidence supports their activation in the brain during epilepsy, and inhibition of the P2X7 receptor reduces the seizure frequency and severity. In this study, we investigate P2X7R-targeted (18F-FTTM) position emission tomography (PET) imaging in a rat model of temporal lobe epilepsy to obtain further insights into the role of P2X7R during epileptogenesis. 18F-FTTM (5-10% radiochemical yield, over 99% radiochemical purity, and a specific activity of 270-300 MBq/nmol, n = 6, EOS) was first synthesized. Then, the rat models induced by intrahippocampal injection of saline (1.2 µL, n = 15) or kainic acid (1.2 µL, 0.5 µg/µL, n = 35) were examined using 18F-FTTM Micro-PET/CT longitudinal imaging, respectively. The imaging results showed that increases in the 18F-FTTM uptake was evident after status epilepticus (SE) in the epileptogenesis-associated brain regions, such as the hippocampus, amygdala, or temporal cortex, and this peaked during the latent period. The histopathological analysis revealed that the P2X7R PET uptake reached a peak at 7 days after SE and was mostly related to microglial activation. Thus, P2X7R-targeted PET imaging agent 18F-FTTM may act as a useful tool for identifying brain inflammation during epilepsy. P2X7R PET is a highly potent longitudinal biomarker of epilepsy and could be of interest to determine the therapeutic windows in epilepsy and to monitor treatment response, and it warrants further clinical studies.

Elevated Blood Glucose is Associated with Severe Exacerbation of Chronic Obstructive Pulmonary Disease.

Background: To evaluate the association of elevated blood glucose with the risk of acute exacerbations in patients with chronic obstructive pulmonary disease (COPD). Methods: Totally 526 consecutive patients with COPD recruited between Jan. 2018 and July 2019 were included in this study. Based on the American Diabetes Association's Standards of Care, these patients were divided into three groups according to HbA1c level: low HbA1c level (HbA1c <5.7%, n=204), moderate HbA1c level (HbA1c 5.7-6.4%, n=165), and high HbA1c level (HbA1c ≥6.5%, n=157). All subjects were followed up for 18 months. Multivariate Cox regression analysis was used to evaluate the predicting value of HbA1c for the time of the next COPD severe exacerbation. Results: Totally 141 (26.8%) patients in the study had at least 1 severe exacerbation. The proportion of patients suffering from at least 1 severe exacerbation was significantly higher (P<0.01) for patients with high (36.3%) and moderate HbA1c levels (25.5%) compared to those with low HbA1c levels (20.6%). Multivariate Cox regression analysis indicated that high (HR=2.74, 95% CI: 1.70-4.41; P<0.01) and moderate HbA1c levels (HR=2.19, 95% CI: 1.39-3.46; P<0.01) were significantly associated with a higher risk of the next severe exacerbation compared with low HbA1c level, after controlling for potential confounders including age, gender, body mass index (BMI), smoking status, disease duration of COPD, frequency of hospitalization due to acute exacerbation of COPD (AECOPD) in the past 12 months, Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages, COPD assessment test (CAT) score, corticosteroids use, hypertension, and cardiovascular diseases. Subgroup analyses also indicated a significant association between HbA1c levels and risk of the next severe exacerbation in different GOLD stages and diabetes status. Conclusion: Elevated blood glucose, no matter with or without diabetes, is significantly associated with a higher risk of the next severe exacerbation for patients with COPD.

Construction of classification models for pathogenic bacteria based on LIBS combined with different machine learning algorithms.

Bacteria, especially foodborne pathogens, seriously threaten human life and health. Rapid discrimination techniques for foodborne pathogens are still urgently needed. At present, laser-induced breakdown spectroscopy (LIBS), combined with machine learning algorithms, is seen as fast recognition technology for pathogenic bacteria. However, there is still a lack of research on evaluating the differences between different bacterial classification models. In this work, five species of foodborne pathogens were analyzed via LIBS; then, the preprocessing effect of five filtering methods was compared to improve accuracy. The preprocessed spectral data were further analyzed with a support vector machine (SVM), a backpropagation neural network (BP), and k-nearest neighbor (KNN). Upon comparing the capacity of the three algorithms to classify pathogenic bacteria, the most suitable one was selected. The signal-to-noise ratio and mean square error of the spectral data after applying a Savitzky-Golay filter reached 17.4540 and 0.0020, respectively. The SVM algorithm, BP algorithm, and KNN algorithm attained the highest classification accuracy for pathogenic bacteria, reaching 98%, 97%, and 96%, respectively. The results indicate that, with the support of a machine learning algorithm, LIBS technology demonstrates superior performance, and the combination of the two is expected to be a powerful tool for pathogen classification.

lncRNA HITT Inhibits Lactate Production by Repressing PKM2 Oligomerization to Reduce Tumor Growth and Macrophage Polarization.

Lactic acid acidifies the tumor microenvironment and promotes multiple critical oncogenic processes, including immune evasion. Pyruvate kinase M2 (PKM2) is a dominant form of pyruvate kinase (PK) expressed in cancers that plays essential roles in metabolic reprograming and lactate production, rendering it as an attractive therapeutic target of cancer. However, the mechanism underlying PKM2 regulation remains unclear. Here, we show that long noncoding RNA (lncRNA) HIF-1α inhibitor at transcription level (HITT) inhibits lactate production in a PKM2-dependent manner. Mechanistically, it physically interacts with PKM2 mapped to a region that has been involved in both dimer (less-active) and tetramer (more-active) formation, inhibiting PKM2 oligomerization and leading to dramatic reduction of PK activity. Under glucose starvation, HITT was reduced as a result of miR-106 induction, which subsequently facilitates PKM2 oligomerization and increases vulnerability to apoptosis under glucose starvation stress. In addition, the interaction also reduces lactate secretion from cancer cells, which subsequently polarizes macrophages toward an M2-like anti-inflammatory phenotype and thus possibly contributes to immune escape in vivo. This study highlights an important role of an lncRNA in regulating PKM2 activity and also reveals a metabolic regulatory effect of PKM2 on macrophage polarization.

Fluorine-18: Radiochemistry and Target-Specific PET Molecular Probes Design.

The positron emission tomography (PET) molecular imaging technology has gained universal value as a critical tool for assessing biological and biochemical processes in living subjects. The favorable chemical, physical, and nuclear characteristics of fluorine-18 (97% ß+ decay, 109.8 min half-life, 635 keV positron energy) make it an attractive nuclide for labeling and molecular imaging. It stands that 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) is the most popular PET tracer. Besides that, a significantly abundant proportion of PET probes in clinical use or under development contain a fluorine or fluoroalkyl substituent group. For the reasons given above, 18F-labeled radiotracer design has become a hot topic in radiochemistry and radiopharmaceutics. Over the past decades, we have witnessed a rapid growth in 18F-labeling methods owing to the development of new reagents and catalysts. This review aims to provide an overview of strategies in radiosynthesis of [18F]fluorine-containing moieties with nucleophilic [18F]fluorides since 2015.