Dynamic Constitutive Relationship of Mg-Gd-Y-Zr-Ag Alloy during High Temperature Deformation Process.

The thermal deformation behavior of the Mg-Gd-Y-Zr-Ag alloy was studied by isothermal hot compression tests at high temperatures. The flow stress increased with increased strain rates and decreased temperatures, first increasing and finally remaining stable with increased strain. A hot processing map was built. Using the processing map and microstructural analysis, the temperature should remain at 673-773 K for this alloy to ensure the deformation quality. The primary softening mechanism is discontinuous dynamic recrystallization (DDRX). Rising temperatures and declining strain rates facilitated the emergence and growth of Dynamic recrystallization (DRX) grains. An original JC (O-JC) model and a modified JC (M-JC) model were established. The M-JC model indicated a better prediction than the O-JC model. Still, it was deficient in predicting flow stresses with insufficient coupling effects. Hence, based on the M-JC model, a newly modified JC (NM-JC) model, which further enhances the interaction between strain and strain rate as well as strain and temperature, is proposed. Its projected values can better align with the tested values.

The valuable role of dynamic 18F FDG PET/CT-derived kinetic parameter Ki in patients with nasopharyngeal carcinoma prior to radiotherapy: A prospective study.

BACKGROUND AND PURPOSE: Dynamic positron emission tomography/computed tomography (PET/CT) served the potential role of characterizing malignant foci. The main objective of this prospective study was to explore the advantage of dynamic PET/CT imaging in characterizing nasopharyngeal carcinoma (NPC). METHODS AND MATERIALS: Patients with probable head and neck disease underwent a local dynamic PET/CT scan followed by a whole-body static scan. Patlak analysis was used to generate parametric influx rate constant (Ki) images from 48 frames obtained from a dynamic PET/CT scan. By delineating the volumes-of-interest (VOIs) of: primary tumor (PT), lymph node (LN), and normal nasopharyngeal tissues (N), we acquired the corresponding Ki mean and SUVmean of each site respectively to perform the quantitative statistical analysis. RESULTS: Qualified images of 71 patients with newly diagnosed NPC and 8 without nasopharyngeal malignant lesions were finally included. We found the correlations between Ki mean-PT and critical clinical features, including clinical stage (r = 0.368), T category (r = 0.643) and EBV-DNA copy status (r = 0.351), and Ki mean-PT differed within the group. SUVmean-PT showed correlations with clinical stage (r = 0.280) and T category (r = 0.472), but could hardly differ systematically within group of clinical features except T category. Ki mean-LN offered the positive correlations with N category (r = 0.294), M category (r = 0.238) and EBV-DNA copy status (r = 0.446), and differed within the group. In addition, Ki mean represented a sensitivity of 94.4 % and a specificity of 100 %, in distinguishing NPC from the non-NPC, when the cut-off was defined as 0.0106. When the cut-off of SUV being defined as 2.03, the sensitivity and specificity were both 100 %. CONCLUSION: Our research confirmed Ki compared favorably to SUV in characterizing NPC and found that Ki can serve as an effective imaging marker of NPC.

Effects of Quenching Cooling Rate on Residual Stress and Mechanical Properties of a Rare-Earth Wrought Magnesium Alloy.

To investigate the effect of quenching rate on microstructure, residual stress (RS) and mechanical properties of a rare-earth wrought magnesium alloy Mg-Gd-Y-Zr-Ag-Er, RS in 20 °C water quenching (WQ (20 °C)), 100 °C water quenching (WQ (100 °C)) or air cooling (AC) conditions were measured and compared with the simulation results, corresponding mechanical properties and microstructure in quenching and aging state were studied. The decrease of quenching rate has little effect on the grain size but makes the twinning disappear, precipitates increase and the texture weakened, leading to easier brittle fracture after aging. WQ (100 °C) is the best quenching condition in this study, with a significant decline in RS and only 4.9% and 3.7% decrease in yield stress (YS) and hardness compared with WQ (20 °C). The results make it feasible to invent an appropriate quenching method of greatly reducing RS while maintaining mechanical properties. The research conclusions would be beneficial to the application of the alloy.

Insight of a Metabolic Prognostic Model to Identify Tumor Environment and Drug Vulnerability for Lung Adenocarcinoma.

Metabolic reprogramming is a novel method for the treatment of malignant tumors. The exploration of metabolism procedures between radiosensitive and radioresistant tumors may provide novel perspectives for lung adenocarcinoma (LUAD) patients after radiation therapy. In our study, metabolic reprogramming and immune response changes were found between radioresistant cell line (A549RR) and its parent cells (A549) using gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Nucleotide/amino acid, lipid, and glucose metabolic process, including Alanine, aspartate and glutamate metabolism, Tryptophan/Tyrosine metabolism, Butanoate metabolism, Purine/Pyrimidine metabolism, were screened out. Then molecular signatures database and The Cancer Genome Atlas Program (TCGA) lung adenocarcinoma datasets were used to identify metabolism-related genes (MRGs) between radiosensitive and radioresistant lung adenocarcinoma (LUAD) cells. A metabolism-based prognostic model, receiver operating characteristic (ROC) curve and nomogram were constructed using Metabolism Score calculated by 14 metabolism-related genes (MRGs). Three independent public datasets, (GSE72094, GSE3141, GSE8894) and one immunotherapy cohort (IMvigor210) were used as external validation cohorts. Expression of 14 hub genes in cells, normal and LUAD specimens were explored by Human Protein Atlas, TIMER2.0 and RT-qPCR. Patients with low-Metabolism Scores were correlated with longer survival times, higher response rates to immune checkpoint inhibitors (ICIs), different immune cell infiltrations and drug vulnerability. Our study demonstrated a comprehensive landscape between radiosensitive and radioresistant LUAD, and provide novel targets for NSCLC, especially those patients received radiation therapy. Moreover, this metabolism-based prognostic model may help to investigate connections between radiosensitivity, immune response, metabolic reprogramming, and patients' prognosis.

Tumor Microbiome in Nasopharyngeal Carcinoma and Its Association With Prognosis.

Introduction: Previous studies have reported a close relationship between cancer and microbes, particularly gut and tumor microbiota; however, the presence of tumor microbiome in nasopharyngeal carcinoma (NPC) and its role in the prognosis of NPC remain unclear. Methods: We collected 64 samples including tissues from 50 patients with NPC (NPC group) and 14 patients with chronic nasopharyngitis (control group) receiver operating characteristics and we applied 16S ribosome RNA gene sequencing of all samples to assess microbiome profiles and immunohistochemistry to detect tumor microbiome in NPC. Results: Patients in the control group harbored higher species diversity than those in the NPC group; however, the beta diversity was more distinct in the NPC group. In total, three genera with statistically significant differences between the two groups were identified. The area under the receiver operating characteristics (ROC) curve (AUC) was calculated using the relative abundance of these three significant genera, and a value of 0.842 was achieved. Furthermore, Turicibacter was confirmed as a potentially independent prognostic factor for NPC patients, and the progression-free survival (PFS) was markedly prolonged in patients with a low relative abundance of Turicibacter compared to patients with a high relative abundance of this genus (cutoff: 0.0046, hazard ratio: 5.10, 95% confidence interval: 2.04-12.77, p = 0.004). Conclusions: The present study provided strong evidence of a correlation between tumor microbiome and NPC; the tumor microbiome may be considered a biomarker for early NPC diagnosis. Turicibacter potentially served as a independently prognostic indicator for NPC patients.

Pathological and genomic phenotype of second neuroendocrine carcinoma during long-term follow-up after radical radiotherapy for nasopharyngeal carcinoma.

BACKGROUND: Second head and neck neuroendocrine carcinoma (NEC) after radical radiotherapy for nasopharyngeal carcinoma (NPC) treatment is rarely reported. The prognosis of second cancer is poor, and our research focuses on finding a breakthrough in the treatment. In this study, we aimed to investigate clinicopathological characteristics and to identify the genomic landscape of second head and neck NECs. METHODS: We collected five second head and neck NEC cases in the recent three years from our patient database. Clinicopathological data and images were obtained. Genomic analysis was performed using high-throughput second generation sequencing. KEGG pathway enrichment analyses between high-frequency mutations were performed using the STRING database. RESULTS: All patients had been diagnosed with second NEC, according to the pathological observations. The interval between diagnosis of NPC and NEC ranged from 10 to 18 years. Two patients had brain or liver metastasis at three and nine months, respectively, after the diagnosis of NEC. Three patients died of the disease with the overall survival time ranging from three to nine months. Commonly altered genes (50%) in second head and neck NECs included TP53, RB1, NOTCH2, PTEN, POLG, KMT2C, U2AF1, EPPK1, ELAC2, DAXX, COL22A1, and ABL1. Those genetic lesions might affect p53 signaling, MAPK signaling, PI3K-Akt signaling, sphingolipid signaling, and neurotrophin signaling pathways. CONCLUSIONS: Second head and neck NECs had poor prognosis. We revealed, for the first time, the mutational landscape, high-frequency somatic mutations, and potential signaling pathways of second head and neck NECs. Its optimal treatment model needs to be further studied in future clinical trials.

Prognostic values, ceRNA network, and immune regulation function of SDPR in KRAS-mutant lung cancer.

BACKGROUND: Serum Deprivation Protein Response (SDPR) plays an important role in formation of pulmonary alveoli. However, the functions and values of SDPR in lung cancer remain unknown. We explored prognostic value, expression pattern, and biological function of SDPR in non-small cell lung cancer (NSCLC) and KRAS-mutant lung cancers. METHODS: SDPR expression was evaluated by quantitative real-time PCR (RT-qPCR), immunohistochemistry (IHC), and Western blot on human NSCLC cells, lung adenocarcinoma tissue array, KRAS-mutant transgenic mice, TCGA and GEO datasets. Prognostic values of SDPR were evaluated by Kaplan-Meier and Cox regression analysis. Bioinformatics implications of SDPR including SDPR-combined transcription factors (TFs) and microRNAs were predicted. In addition, correlations between SDPR, immune checkpoint molecules, and tumor infiltration models were illustrated. RESULTS: SDPR expression was downregulated in tumor cells and tissues. Low SDPR expression was an independent factor that correlated with shorter overall survival of patients both in lung cancer and KRAS-mutant subgroups. Meanwhile, ceRNA network was constructed to clarify the regulatory and biological functions of SDPR. Negative correlations were found between SDPR and immune checkpoint molecules (PD-L1, TNFRSF18, TNFRSF9, and TDO2). Moreover, diversity immune infiltration models were observed in NSCLC with different SDPR expression and copy number variation (CNV) patterns. CONCLUSIONS: This study elucidated regulation network of SDPR in KRAS-mutant NSCLC, and it illustrated correlations between low SDPR expression and suppressed immune system, unfolding a prognostic factor and potential target for the treatment of lung cancer, especially for KRAS-mutant NSCLC.

Targeted therapies for RET-fusion cancer: Dilemmas and breakthrough.

Genomic profiling has revolutionized treatment options for patients with oncogene-driven cancers, such as epidermal growth factor receptor (EGFR) mutant carcinoma. Rearranged during transfection (RET) rearrangement, as one of the main activated oncogenes, has been well studied and found to be involved in the malignant behavior of carcinogenesis, resulting in acquired resistance to EGFR tyrosine kinase inhibitors and inducing an intrinsic resistance to immunotherapy. Thus, targeted therapies have been investigated against RET arrangement cancers, including several multi-kinase inhibitors and selective RET inhibitors. However, modest efficacy, a relatively high rate of toxicity, and poor effectiveness against brain metastasis are common limitations of multi-targeted novel molecular inhibitors. A promising prospect was shown recently in selective RET inhibitors in several ongoing clinical trials. In this review, we reviewed the concurrent dilemmas of targeted therapies against RET arrangement cancer from preclinical and clinical studies and proposed several clinical considerations for clinical practice prospectively.

Impact of molecular subtypes on metastatic behavior and overall survival in patients with metastatic breast cancer: A single-center study combined with a large cohort study based on the Surveillance, Epidemiology and End Results database.

Breast cancer is a highly heterogeneous disease at the molecular level and >90% of mortalities are due to metastasis and its associated complications. The present study determined the impact of molecular subtypes on metastatic behavior and overall survival (OS) of patients with metastatic breast cancer. The influence of molecular subtypes on the sites and number of metastases in 166 patients with metastatic breast cancer from a single center were assessed; and the influence of molecular subtypes on the sites and number of metastases and OS in 15,322 metastatic cases among 329,770 patients with primary breast cancer from the Surveillance, Epidemiology and End Results database were assessed. Analysis of both datasets revealed that different molecular subtypes exhibited differences in the prevalence of different metastatic sites and number of metastases. A larger proportion of bone metastasis was observed in the hormone receptor (HR)+/human epidermal growth factor receptor 2 (HER2)+ subtype than in other subtypes, more lung metastasis was observed in the HR-/HER2+ subtype and more liver metastasis occurred in the HR+/HER2+ and HR-/HER2+ subtypes. Single-site metastasis was more common for the HR+/HER2- subtype than in other subtypes, while 2-3 sites of metastases were more common for the HR+/HER2+ subtype and ≥4 sites of metastases were more frequent in the HR-/HER2+ and HR-/HER2- subtypes. The mean OS of patients with primary breast cancer in the HR+/HER2- subtype group was the longest (78.5 months), while the HR-/HER2- group had the shortest mean OS (69.1 months). The mean OS of the metastatic HR+/HER2+ group was the longest (46.0 months), while the mean OS of the metastatic HR-/HER2- group was the shortest (18.5 months). In conclusion, the results of the present study suggested that different molecular subtypes of breast cancer have different metastatic behavior, as well as mean OS.

Dual inhibition of VEGF and PARP suppresses KRAS-mutant colorectal cancer.

The addition of bevacizumab to chemotherapy has prolonged overall and progression-free survival rates for metastatic colorectal cancer (mCRC). However, KRAS-mutant (KRAS-mut) CRC, lacking an ideal targeted agent, represents an inferior-response subgroup of patients. In the present study, we investigated a combination approach of bevacizumab + olaparib in KRAS-mut CRC in a preclinical setting. The combined therapy effectively prevented tumor growth in a KRAS-mut cancer cell-derived xenograft model, although this effect was not observed in vitro. Under bevacizumab treatment, we detected intratumor hypoxia and impaired homologous recombination repair (HRR), accompanied by vascular regression. We explored the underlying mechanism of this combined therapy by mimicking a hypoxic condition in vitro using cobalt chloride (CoCl2). The results showed that hypoxia impairs HRR and therefore sensitized KRAS-mut CRC cell lines HCT-116, SW620, and Lovo to olaparib. Furthermore, under this hypoxic condition, olaparib could arrest the cell cycle in the G2/M phase, increase DNA damage and dramatically induce cell apoptosis in KRAS-mut CRC cells. Taken together, these results indicated that the combination of bevacizumab + olaparib could be a potential therapeutic approach in a KRAS-mut CRC cohort.

Ischemia-reperfusion injury of brain induces endothelial-mesenchymal transition and vascular fibrosis via activating let-7i/TGF-ßR1 double-negative feedback loop.

Let-7i modulates the physical function and inflammation in endothelial cells (ECs). However, whether the let-7i of ECs involves in brain vasculature and ischemic stroke is unknown. Using inducible Cadherin5-Cre lineage-tracking mice, a loxp-RNA-sponge conditional knockdown of let-7 in ECs- induced increase of transforming growth factor-ß receptor type 1 (TGF-ßR1), endothelial-mesenchymal transition (endMT), vascular fibrosis, and opening of the brain-blood barrier (BBB). By this lineage-tracking mice, we found that ECs underwent endMT after transient middle cerebral artery occlusion (MCAO). Through specifically overexpressed let-7i in ECs, we found that it reduced TGF-ßR1, endMT, and vascular fibrosis. Furthermore, this overexpression reduced the infarct volume and leakage of the BBB, and improved the neurological function. Further, the expression of let-7i decreased after MCAO, but was reversed by antagonist of TGF-ßR1 or inhibition of Mek phosphorylation. And the inhibition of Mek attenuated the vascular fibrosis after MCAO. In summary, we concluded that ischemic stroke activates a let-7i/TGF-ßR1 double-negative feedback loop, thereby inducing endMT and vascular fibrosis. These results suggest that endMT is a potential target for the treatment of cerebral vascular fibrosis.

EGFR-TKI resistance promotes immune escape in lung cancer via increased PD-L1 expression.

BACKGROUND: The ATLANTIC trial reported that higher PD-L1 expression in tumors was involved in a higher objective response in patients with EGFR+/ALK+ non-small cell lung cancer (NSCLC), indicating the possibility of anti-PD-1/PD-L1 therapy as a third-line (or later) treatment for advanced NSCLC. Therefore, the determination of status and regulatory mechanisms of PD-L1 in EGFR mutant NSCLC before and after acquired EGFR-TKIs resistance are meaningful. METHODS: The correlation among PD-L1, c-MET, and HGF was analyzed based on TCGA datasheets and paired NSCLC specimens before and after acquired EGFR-TKI resistance. EGFR-TKI resistant NSCLC cells with three well-known mechanisms, c-MET amplification, hepatocyte growth factor (HGF), and EGFR-T790M, were investigated to determinate PD-L1 expression status and immune escape ability. PD-L1-deleted EGFR-TKIs sensitive and resistant cells were used to evaluate the immune escape ability of tumors in mice xenograft models. RESULTS: Positive correlations were found among PD-L1, c-MET, and HGF, based on TCGA datasheets and paired NSCLC specimens. Moreover, the above three resistant mechanisms increased PD-L1 expression and attenuated activation and cytotoxicity of lymphocytes in vitro and in vivo, and downregulation of PD-L1 partially restored the cytotoxicity of lymphocytes. Both MAPK and PI3K pathways were involved in the three types of resistance mechanism-induced PD-L1 overexpression, whereas the NF-kappa B pathway was only involved in T790M-induced PD-L1 expression. CONCLUSIONS: HGF, MET-amplification, and EGFR-T790M upregulate PD-L1 expression in NSCLC and promote the immune escape of tumor cells through different mechanisms.

Inhibition of NF-κB improves sensitivity to irradiation and EGFR-TKIs and decreases irradiation-induced lung toxicity.

Resistance to radiotherapy and to EGFR tyrosine kinase inhibitors (EGFR-TKIs), as well as therapy-related lung toxicity, are serious problems in the treatment of lung cancer. NF-κB has been reported to be associated with radioresistance. Therefore, we evaluated its effects on sensitivity to irradiation and to EGFR-TKIs; irradiation-induced lung toxicity; and the effects of irradiation on sensitivity to EGFR-TKIs. We used IKKß inhibitor IMD 0354 or p65 depletion to explore their effects on sensitivity to irradiation and to EGFR-TKIs in vitro and in vivo. We evaluated the efficacy of IMD 0354 in a radiation-induced pulmonary-fibrosis mouse model. Irradiation enhanced activation and expression of MET and therefore suppressed the sensitivity of lung cancer cells to irradiation or EGFR-TKIs. Inhibition of NF-κB by IMD 0354 or by p65 depletion reversed irradiation-induced MET activation and increased the sensitivity of lung cancer cells to irradiation, to EGFR-TKIs and to the combination thereof in vitro and in vivo. In addition, IMD 0354 significantly reduced lung toxicity in a murine model of irradiation-induced pneumonia and lung fibrosis. These findings indicated that NF-κB inhibition can improve sensitivity to irradiation and to EGFR-TKIs and can decrease irradiation-induced lung toxicity in lung cancer.

Let-7i attenuates human brain microvascular endothelial cell damage in oxygen glucose deprivation model by decreasing toll-like receptor 4 expression.

The let-7 family of microRNAs (miRNAs) plays an important role on endothelial cell function. However, there have been few studies on their role under ischemic conditions. In this study, we demonstrate that let-7i, belonging to the let-7 family, rescues human brain microvascular endothelial cells (HBMECs) in an oxygen-glucose deprivation (OGD) model. Our data show that the expression of let-7 family miRNAs was downregulated after OGD. Overexpression of let-7i significantly alleviated cell death and improved survival of OGD-treated HBMECs. Let-7i also protected permeability in an in vitro blood brain barrier (BBB) model. Further, let-7i downregulated the expression of toll-like receptor 4 (TLR4), an inflammation trigger. Moreover, overexpression of let-7i decreased matrix metallopeptidase 9 (MMP9) and inducible nitric oxide synthase (iNOS) expression under OGD. Upon silencing TLR4 expression in HBMECs, the anti-inflammatory effect of let-7i was abolished. Our research suggests that let-7i promotes OGD-induced inflammation via downregulating TLR4 expression.

Hepatocyte growth factor reduces sensitivity to the epidermal growth factor receptor-tyrosine kinase inhibitor, gefitinib, in lung adenocarcinoma cells harboring wild-type EGFR.

Epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) therapy is an option for lung cancers harboring wild-type EGFR when chemotherapeutic reagents have failed. In this study, we found that the EGFR-TKI, gefitinib, modestly suppressed proliferation of the lung cancer cell lines, A549 and H358, which both harbor wild-type EGFR. Treatment with hepatocyte growth factor (HGF) reduced the sensitivity to gefitinib, whereas sensitivity was restored by treatment with an HGF antibody, a MET inhibitor, or depletion of MET but not ErbB3 gene. Moreover, both PI3K/mTOR inhibitors and MEK inhibitors suppressed proliferation of A549 cells, whereas only PI3K/mTOR inhibitors effectively suppressed cell viability of EGFR mutant PC-9 cells. Our findings suggest that HGF reduced the gefitinib sensitivity through MET and downstream PI3K and MAPK pathways. Combined use of EGFR-TKI and MET inhibitors or inhibition of downstream signaling molecules might be a better second or third line choice for a group of patients with advanced lung cancer harboring wild-type EGFR.

MiR-20a Induces Cell Radioresistance by Activating the PTEN/PI3K/Akt Signaling Pathway in Hepatocellular Carcinoma.

PURPOSE: To investigate the role of miR-20a in hepatocellular carcinoma (HCC) cell radioresistance, which may reveal potential strategies to improve treatment. METHODS AND MATERIALS: The expression of miR-20a and PTEN were detected in HCC cell lines and paired primary tissues by quantitative real-time polymerase chain reaction. Cell radiation combined with colony formation assays was administrated to discover the effect of miR-20a on radiosensitivity. Bioinformatics prediction and luciferase assay were used to identify the target of miR-20a. The phosphatidylinositol 3-kinase inhibitor LY294002 was used to inhibit phosphorylation of Akt, to verify whether miR-20a affects HCC cell radioresistance through activating the PTEN/PI3K/Akt pathway. RESULTS: MiR-20a levels were increased in HCC cell lines and tissues, whereas PTEN was inversely correlated with it. Overexpression of miR-20a in Bel-7402 and SMMC-7721 cells enhances their resistance to the effect of ionizing radiation, and the inhibition of miR-20a in HCCLM3 and QGY-7701 cells sensitizes them to it. PTEN was identified as a direct functional target of miR-20a for the induction of radioresistance. Overexpression of miR-20a activated the PTEN/PI3K/Akt signaling pathway. Additionally, the kinase inhibitor LY294002 could reverse the effect of miR-20a-induced radioresistance. CONCLUSION: MiR-20a induces HCC cell radioresistance by activating the PTEN/PI3K/Akt pathway, which suggests that miR-20a/PTEN/PI3K/Akt might represent a target of investigation for developing effective therapeutic strategies against HCC.