Glycyrrhizin Protects Submandibular Gland Against Radiation Damage by Enhancing Antioxidant Defense and Preserving Mitochondrial Homeostasis.

Aims: Radiotherapy inevitably causes radiation damage to the salivary glands (SGs) in patients with head and neck cancers (HNCs). Excessive reactive oxygen species (ROS) levels and imbalanced mitochondrial homeostasis are serious consequences of ionizing radiation in SGs; however, there are few mitochondria-targeting therapeutic approaches. Glycyrrhizin is the main extract of licorice root and exhibits antioxidant activity to relieve mitochondrial damage in certain oxidative stress conditions. Herein, the effects of glycyrrhizin on irradiated submandibular glands (SMGs) and the related mechanisms were investigated. Results: Glycyrrhizin reduced radiation damage in rat SMGs at both the cell and tissue levels, and promoted saliva secretion in irradiated SMGs. Glycyrrhizin significantly downregulated high-mobility group box-1 protein (HMGB1) and toll-like receptor 5 (TLR5). Moreover, glycyrrhizin significantly suppressed the increases in malondialdehyde and glutathione disulfide (GSSG) levels; elevated the activity of some critical antioxidants, including superoxide dismutase, catalase, glutathione peroxidase, and glutathione (GSH); and increased the GSH/GSSG ratio in irradiated cells. Importantly, glycyrrhizin effectively enhanced thioredoxin-2 levels and scavenged mitochondrial ROS, inhibited the decline in mitochondrial membrane potential, improved adenosine triphosphate synthesis, preserved the mitochondrial ultrastructure, activated the proliferator-activated receptor-gamma coactivator-1alpha (PGC-1α)/nuclear respiratory factor 1/2 (NRF1/2)/mitochondrial transcription factor A (TFAM) signaling pathway, and inhibited mitochondria-related apoptosis in irradiated SMG cells and tissues. Innovation: Radiotherapy causes radiation sialadenitis in HNC patients. Our data suggest that glycyrrhizin could be a mitochondria-targeted antioxidant for the prevention of radiation damage in SGs. Conclusion: These findings demonstrate that glycyrrhizin protects SMGs from radiation damage by downregulating HMGB1/TLR5 signaling, maintaining intracellular redox balance, eliminating mitochondrial ROS, preserving mitochondrial homeostasis, and inhibiting apoptosis.

Randomized Trial of First-Line Tyrosine Kinase Inhibitor With or Without Radiotherapy for Synchronous Oligometastatic EGFR-Mutated Non-Small Cell Lung Cancer.

BACKGROUND: Adding radiotherapy (RT) to systemic therapy improves progression-free survival (PFS) and overall survival (OS) in oligometastatic non-small cell lung cancer (NSCLC). Whether these findings translate to epidermal growth factor receptor (EGFR)-mutated NSCLC remains unknown. The SINDAS trial (NCT02893332) evaluated first-line tyrosine kinase inhibitor (TKI) therapy for EGFR-mutated synchronous oligometastatic NSCLC and randomized to upfront RT vs no RT; we now report the prespecified interim analysis at 68% accrual. METHODS: Inclusion criteria were biopsy-proven EGFR-mutated adenocarcinoma (per amplification refractory mutation system or next generation sequencing), with synchronous (newly diagnosed, treatment naïve) oligometastatic (≤5 metastases; ≤2 lesions in any one organ) NSCLC without brain metastases. All patients received a first-generation TKI (gefitinib, erlotinib, or icotinib), and randomization was between no RT vs RT (25-40 Gy in 5 fractions depending on tumor size and location) to all metastases and the primary tumor/involved regional lymphatics. The primary endpoint (intention to treat) was PFS. Secondary endpoints included OS and toxicities. All statistical tests were 2-sided. RESULTS: A total of 133 patients (n = 65 TKI only, n = 68 TKI with RT) were enrolled (2016-2019). The median follow-up was 23.6 months. The respective median PFS was 12.5 months vs 20.2 months (P < .001), and the median OS was 17.4 months vs 25.5 months (P < .001) for TKI only vs TKI with RT. Treatment yielded no grade 5 events and a 6% rate of symptomatic grade 3-4 pneumonitis in the TKI with RT arm. Based on the efficacy results of this prespecified interim analysis, the ethics committee recommended premature cessation of this trial. CONCLUSIONS: As compared with a first-line TKI alone, addition of upfront local therapy using RT statistically significantly improved PFS and OS for EGFR-mutated NSCLC.

Salidroside Ameliorates Radiation Damage by Reducing Mitochondrial Oxidative Stress in the Submandibular Gland.

Radiotherapy for patients with head and neck cancer inevitably causes radiation damage to salivary glands (SGs). Overproduction of reactive oxygen species (ROS) leads to mitochondrial damage and is critical in the pathophysiology of SG radiation damage. However, mitochondrial-targeted treatment is unavailable. Herein, both in vitro and in vivo models of radiation-damaged rat submandibular glands (SMGs) were used to investigate the potential role of salidroside in protecting irradiated SGs. Cell morphology was observed with an inverted phase-contrast microscope. Malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), mitochondrial ROS, mitochondrial membrane potential (MMP), and ATP were measured using relevant kits. The mitochondrial ultrastructure was observed under transmission electron microscopy. Cell apoptosis was determined by Western blot and TUNEL assays. Saliva was measured from Wharton's duct. We found that salidroside protected SMG cells and tissues against radiation and improved the secretion function. Moreover, salidroside enhanced the antioxidant defense by decreasing MDA, increasing SOD, CAT, and GSH, and scavenging mitochondrial ROS. Furthermore, salidroside rescued the mitochondrial ultrastructure, preserved MMP and ATP, suppressed cytosolic cytochrome c and cleaved caspase 3 expression, and inhibited cell apoptosis. Together, these findings first identify salidroside as a mitochondrial-targeted antioxidant for preventing SG radiation damage.

Two single nucleotide polymorphisms in TSLP gene are associated with asthma susceptibility in Chinese Han population.

BACKGROUND: Asthma is a chronic inflammatory disease of the airway that is mediated by T-helper 2(TH2) cells. Thymic stromal lymphopoietin (TSLP) can aggravate asthmatic lung inflammation by activating dendritic cells (DCs) to promote TH2 differentiation. TSLP promoter polymorphisms are associated with susceptibility to bronchial asthma in Japanese population. We sought to determine whether single nucleotide polymorphisms (SNPs) in TSLP gene are associated with asthma in Chinese Han population. OBJECTIVE: To analyze the polymorphism of the two SNPs Rs2289276 and Rs2289278 in TSLP gene and to evaluate the association between the two SNPs and asthma susceptibility in Chinese Han population by using case-control study. METHODS: five hundred and thirty one asthmatic patients and 540 age-sex matched normal controls were collected and DNA were extracted from peripheral blood, then the genotypes of SNPs Rs2289276 and Rs2289278 in TSLP gene were detected with polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP), genotype and allele frequencies were calculated and analyzed with Chi-square test. RESULTS: Frequencies of CC/CT/TT genotypes at Rs2289276 site were 0.4706/0.4392/0.0902 in the asthmatic patients and 0.5604/0.3800/0.0595 in the healthy controls. Frequencies of CC/CG/GG genotypes at Rs2289278 site were 0.6502/0.2966/0.0532 in the asthmatic patients and 0.5795/0.3428/0.0777 in the healthy controls. The genotype and allele frequencies of the two SNPs in asthma patients were significantly different from those in the healthy controls. Rs2289278 C allele was correlated with decreased FEV(1): FVC (P ≤ .05). CONCLUSIONS: TSLP variants are significantly associated with bronchial asthma. TSLP might be a new therapeutic target molecule for asthma.

[Changes of exhaled nitric oxide and peripheral blood eosinophils in children with asthma].

OBJECTIVE: This study examined the levels of exhaled nitric oxide (eNO) and peripheral blood eosinophils (EOS) as well as the correlation between the two markers in children with bronchial asthma (AS),AS complicated by allergic rhinitis (AS/AR) and chronic cough variant asthma (CVA), in order to explore the value of eNOS detection in children with AS. METHODS: The eNO level was measured using light-emitting electrochemical photometry in 12 children with AS, 29 children with AS/AR and 10 children with CVA. Peripheral blood EOS was counted by blood cell counter (Coulter JT). Forced expiratory volume in one second (FEV1) was assessed by lung function measurement. Thirty children without atopic disease and acute respiratory infection as well as without a family history of atopic diseasea served as the control group. RESULTS: The levels of eNO and blood EOS in the AS, the AS/AR and the CVA groups were significantly higher than those in the control group (p<0.01). The AS/AR group showed increased levels of eNO (50.3 + or - 6.7 ppb) and EOS (5.9 + or -4.2 x 109 ) compared with the AS (30.5 + or - 8.8 ppb and 4.2 + or - 3.2 x 109 respectively) and the CVA groups (26.0 + or - 3.2 ppb and 3.7 + or - 6.9 x 109 respectively) (p<0.05). There were no significant differences in eNO and EOS levels between the AS and the CVA groups. The eNO level was positively correlated with the EOS level (r=0.51, p<0.05), but not with FEV1 (r=0.144, p>0.05) in the AS group. CONCLUSIONS: NO is highly expressed in children with symptoms of atopy and can reflect the levels of eosinophilic airway inflammation in children with AS.