scholarly journals Dietary nitrate supplementation prevents radiotherapy-induced xerostomia

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Xiaoyu Feng ◽  
Zhifang Wu ◽  
Junji Xu ◽  
Yipu Xu ◽  
Bin Zhao ◽  
...  

Management of salivary gland hypofunction caused by irradiation (IR) therapy for head and neck cancer remains lack of effective treatments. Salivary glands, especially the parotid gland, actively uptake dietary nitrate and secrete it into saliva. Here, we investigated the effect of dietary nitrate on the prevention and treatment of IR-induced parotid gland hypofunction in miniature pigs, and elucidated the underlying mechanism in human parotid gland cells (hPGCs). We found that nitrate administration prevented IR-induced parotid gland damage in a dose-dependent manner, by maintaining the function of irradiated parotid gland tissue. Nitrate could increase sialin expression, a nitrate transporter expressed in the parotid gland, making the nitrate-sialin feedback loop that facilitates nitrate influx into cells for maintaining cell proliferation and inhibiting apoptosis. Furthermore, nitrate enhanced cell proliferation via the epidermal growth factor receptor (EGFR)-protein kinase B (AKT)-mitogen-activated protein kinase (MAPK) signaling pathway in irradiated parotid gland tissue. Collectively, nitrate effectively prevented IR-induced xerostomia via the EGFR–AKT-MAPK signaling pathway. Dietary nitrate supplementation may provide a novel, safe, and effective way to resolve IR-induce xerostomia.

2017 ◽  
Vol 95 (3) ◽  
pp. 415-420 ◽  
Author(s):  
Yeying Wang ◽  
Bing Hai ◽  
Xiaoqun Niu ◽  
Li Ai ◽  
Yu Cao ◽  
...  

Obstructive sleep apnea (OSA) is a breathing disorder during sleep, with a most prominent character of chronic intermittent hypoxia (CIH), which induces the generation of reactive oxygen species (ROS) that damages multiple tissues and causes metabolic disorders. In this study, we established a rat model of varying OSA with different grades of CIH (12.5% O2, 10% O2, 7.5% O2, and 5% O2) for 12 weeks, and found that CIH stimulated insulin secretion, reduced the insulin:proinsulin ratio in pancreatic tissue, and caused pancreatic tissue lesions and cell apoptosis in a dose-dependent manner. Moreover, CIH promoted the production of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6, and activated mitogen-activated protein kinase (MAPK) family members, extracellular regulated protein kinase (ERK), c-Jun N-terminal kinase (JNK), and P38, depending on the O2 concentration. In summary, CIH disturbed insulin secretion, and caused inflammation, lesions, and cell apoptosis in pancreatic tissue via the MAPK signaling pathway, which may be of great significance for clinical treatment of OSA and type 2 diabetes mellitus (T2DM).


Author(s):  
Xiaowen Chen ◽  
Jianli Chen

This study intended to investigate the effects of miR-3188 on breast cancer and to reveal the possible molecular mechanisms. miR-3188 was upregulated and TUSC5 was downregulated in breast cancer tissues and MCF-7 cells compared to normal tissue and MCF-10 cells. After MCF-7 cells were transfected with miR-3188 inhibitor, cell proliferation and migration were inhibited, whereas apoptosis was promoted. Luciferase reporter assay suggested that TUSC5 was a target gene of miR-3188. In addition, miR-3188 overexpression increased the p-p38 expression, while miR-3188 suppression decreased the p-p38 expression significantly. miR-3188 regulated breast cancer progression via the p38 MAPK signaling pathway. In conclusion, miR-3188 affects breast cancer cell proliferation, apoptosis, and migration by targeting TUSC5 and activating the p38 MAPK signaling pathway. miR-3188 may serve as a potential therapeutic agent for the treatment of breast cancer.


Author(s):  
Shan Lei ◽  
Zhiwei He ◽  
Tengxiang Chen ◽  
Xingjun Guo ◽  
Zhirui Zeng ◽  
...  

Abstract Background Accumulation evidence indicates the vital role of long non-coding RNAs (lncRNAs) in tumorigenesis and the progression of malignant tumors, including pancreatic cancer (PC). However, the role and the molecular mechanism of long non-coding RNA 00976 is unclear in pancreatic cancer. Methods In situ hybridization (ISH) and qRT-PCR was performed to investigate the association between linc00976 expression and the clinicopathological characteristics and prognosis of patients with PC. Subsequently, linc00976 over-expression vector and shRNAs were transfected into PC cells to up-regulate or down-regulate linc00976 expression. Loss- and gain-of function assays were performed to investigate the role of linc00976 in proliferation and metastasis in vitro and vivo. ITRAQ, bioinformatic analysis and rescue assay were used to illustrate the ceRNA mechanism network of linc00976/miR-137/OTUD7B and its downstream EGFR/MAPK signaling pathway. Results linc00976 expression was overexpressed in PC tissues and cell lines and was positively associated with poorer survival in patients with PC. Function studies revealed that linc00976 knockdown significantly suppressed cell proliferation, migration and invasion in vivo and in vitro, whereas its overexpression reversed these effects. Based on Itraq results and online database prediction, Ovarian tumor proteases OTUD7B was found as a downstream gene of linc00976, which deubiquitinated EGFR mediates MAPK signaling activation. Furthermore, Bioinformatics analysis and luciferase assays and rescue experiments revealed that linc00976/miR137/OTUD7B established the ceRNA network modulating PC cell proliferation and tumor growth. Conclusion The present study demonstrates that linc00976 enhances the proliferation and invasion ability of PC cells by upregulating OTUD7B expression, which was a target of miR-137. Ultimately, OTUD7B mediates EGFR and MAPK signaling pathway, suggesting that linc00976/miR-137/OTUD7B/EGFR axis may act as a potential biomarker and therapeutic target for PC.


2018 ◽  
Vol 315 (3) ◽  
pp. F503-F511 ◽  
Author(s):  
Zhizhi Zhuang ◽  
Jia Xiao ◽  
Xinxin Chen ◽  
Xiaohan Hu ◽  
Ruidian Li ◽  
...  

G protein pathway suppressor 2 (GPS2) is a multifunctional protein and transcriptional regulation factor that is involved in the G protein MAPK signaling pathway. It has been shown that the MAPK signaling pathway plays an important role in the regulation of renal large-conductance Ca2+-activated potassium (BK) channels. In this study, we investigated the effects of GPS2 on BK channel activity and protein expression. In human embryonic kidney (HEK) BK stably expressing cells transfected with either GPS2 or its vector control, a single-cell recording showed that GPS2 significantly increased BK channel activity ( NPo), increasing BK open probability ( Po), and channel number ( N) compared with the control. In Cos-7 cells and HEK 293 T cells, GPS2 overexpression significantly enhanced the total protein expression of BK in a dose-dependent manner. Knockdown of GPS2 expression significantly decreased BK protein expression, while increasing ERK1/2 phosphorylation. Knockdown of ERK1/2 expression reversed the GPS2 siRNA-mediated inhibition of BK protein expression in Cos-7 cells. Pretreatments of Cos-7 cells with either the lysosomal inhibitor bafilomycin A1 or the proteasomal inhibitor MG132 partially reversed the inhibitory effects of GPS2 siRNA on BK protein expression. In addition, feeding a high-potassium diet significantly increased both GPS2 and BK protein abundance in mice. These data suggest that GPS2 enhances BK channel activity and its protein expression by reducing ERK1/2 signaling-mediated degradation of the channel.


2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Li-qian Zhang ◽  
Rong-wei Lv ◽  
Xiang-dong Qu ◽  
Xian-jun Chen ◽  
Hong-sheng Lu ◽  
...  

Aloesin is an active constituent of the herb aloe vera and plays a crucial role in anti-inflammatory activity, ultraviolet protection, and antibacterium. We investigated the role and possible mechanisms of aloesin in the cell growth and metastasis of ovarian cancer. It was found that aloesin inhibited cell viability and cell clonality in a dose-dependent manner. It arrests the cell cycle at the S-phase and induced apoptosis in SKOV3 cells. In an in vivo experiment, it was observed that aloesin inhibited tumor growth. Moreover, it inhibited migration and invasion of cancer in SKOV3 cells. Interestingly, members from the mitogen-activated protein kinase (MAPK) signaling family became less phosphorylated as the aloesin dose increased. This suggests that aloesin exerts its anticancer effect through the MAPK signaling pathway. Our data also highlights the possibility of using aloesin as a novel therapeutic drug for ovarian cancer treatment.


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