Nitrites play multiple characteristic functions in invasion and metastasis of hepatic cancer cells, but the exact mechanism is not yet known. Cancer cells can maintain the malignant characteristics via clearance of excess mitochondria by mitophagy. The purpose of this article was to determine the roles of nitrite, reactive oxygen species (ROS) and hypoxia inducing factor 1 alpha (HIF-1 α) in mitophagy of hepatic cancer cells. After exposure of human hepatocellular carcinoma SMMC-7721 cells to a serial concentrations of sodium nitrite for 24 h under normal oxygen, the maximal cell vitality was increased by 16 mg x (-1) sodium nitrite. In addition, the potentials of migration and invasion for SMMC-7721 cells were increased significantly at the same time. Furthermore, sodium nitrite exposure displayed an increase of stress fibers, lamellipodum and perinuclear mitochondrial distribution by cell staining with Actin-Tracker Green and Mito-Tracker Red, which was reversed by N-acetylcysteine (NAC, a reactive oxygen scavenger). DCFH-DA staining with fluorescent microscopy showed that the intracellular level of ROS concentration was increased by the sodium nitrite treatment. LC3 immunostaining and Western blot results showed that sodium nitrite enhanced cell autophagy flux. Under the transmission electron microscopy (TEM), more autolysosomes formed after sodium nitrite treatment and NAC could prevent autophagosome degradation. RT-PCR results indicated that the expression levels of COX I and COXIV mRNA were decreased significantly after sodium nitrite treatment. Meanwhile, laser scanning confocal microscopy showed that sodium nitrite significantly reduced mitochondrial mass detected by Mito-Tracker Green staining. The expression levels of HIF-1α, Beclin-1 and Bnip3 (mitophagy marker molecular) increased remarkably after sodium nitrite treatment, which were reversed by NAC. Our results demonstrated that sodium nitrite (16 mg x L(-1)) increased the potentials of invasion and migration of hepatic cancer SMMC-7721 cells through induction of ROS and HIF-1α mediated mitophagy.
Acetylcysteine ; pharmacology ; Autophagy ; Carcinoma, Hepatocellular ; pathology ; Cell Line, Tumor ; Cell Movement ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; metabolism ; Liver Neoplasms ; pathology ; Mitochondrial Degradation ; Neoplasm Invasiveness ; Nitrites ; metabolism ; Reactive Oxygen Species ; metabolism ; Sodium Nitrite ; pharmacology

Objective: To observe the clinical efficacy of heat-sensitive moxibustion plus Western medicine in treating patients with diabetic peripheral neuropathy (DPN). Methods: A total of 70 patients with DPN were divided into an observation group and a control group by sealed envelope method combined with the random number table method, with 35 cases in each group. The control group was treated with routine medicine, and the observation group was treated with heat-sensitive moxibustion on the basis of the treatment in the control group. After 2 courses of treatment, the scores of Toronto clinical scoring system (TCSS) and vibration perception threshold (VPT) in both groups were observed, and the clinical efficacy was compared. Results: During treatment, 3 cases dropped out in the control group and 4 cases in the observation group. After treatment, the total effective rate in the observation group was higher than that in the control group (P<0.05). The scores of TCSS and VPT in both groups decreased after treatment, and the intra-group comparison showed statistical significance (both P<0.05). The scores of TCSS and VPT in the observation group were lower than those in the control group, and the differences were statistically significant (both P<0.05). Conclusion: Heat-sensitive moxibustion plus Western medicine can improve the symptoms in patients with DPN, and has a better curative effect than the Western medicine alone.

The quality of higher medical education is generally concerned and valued in medical education systems of various countries.Postgraduate tutors play a very important role in higher medical education and tutor quality is directly related to the quality of postgraduate education.The article summarizes experience and knowledge of years in medical postgraduate education management and construction of supervisor team work and discusses how to strengthen the construction of postgraduate tutor team of higher medical education combined with examples.The article points out the problems and defects in the construction of the current tutor team and puts forward practical and constructive suggestions for the reference of higher education management counterparts.

Objective To investigate the effect of inhibiting the expression of RNA component of mitochondrial RNA processing endoribonuclease(RMRP)on the proliferation and invasion of human lung cancer cell line A549 in order to provide evidence to support the research on NSCLC mechanism.Methods A total of 122 cases of patients who underwent surgical treatment were selected in Jiaozuo People's Hospital from March 2016 to March 2021.In the same period,50 healthy people from physical examination center were selected as the control group.RT-qPCR was used to detect the expressions of RMRP in blood and tissues.Human lung cancer cell line A549 was cultured and divided into si-RMRP group,siRNA-NC group and blank group.RT-qPCR,CCK-8 and Transwell assays were used to detect the expression of RMRP,proliferation activity and cell counting of invasive cells.Results The rel-ative expression level of RMRP in the blood of NSCLC patients was significantly higher than that of control group(P<0.001).The relative expression level of RMRP in NSCLC tissues was significantly higher than the adjacent tissues(P<0.001).The relative expression level of RMRP in blood and tissues of patients with poorly differenti-ated,lymph node metastasis and TNM stage Ⅲ compared with moderate to highly differentiated,no lymph node metastasis and TNM stage Ⅰ-Ⅱ were significantly increased(P<0.05).The relative expression level of RMRP in the cells of the si-RMRP group was lower than that of blank and the siRNA-NC group(P<0.001).Compared with the blank group and the siRNA-NC group,the absorbance(A)value of cells at 24,48,72 and 96 h in the si-RMRP group was decreased(P<0.05).The number of invasion cells in the si-RMRP group was lower than that in the blank group and the siRNA-NC group(F=27.765,P<0.001).Conclusions The relative expression levels of RMRP in blood and tissues of NSCLC patients are increased.Down-regulation of the expres-sion of RMRP gene in A549 cells can inhibit cell proliferation and reduce cell invasion.

Reactive nitrogen species (RNS) affects intracellular redox balance and induces post-translational modification of proteins. Moreover, RNS, as the signal molecule, participates in the transduction of cellular signals under physiological conditions. However, excessive RNS can induce nitrosative stress and then damage cells, and thereby may play a role in the tumor initiation and progression. Thus, we discussed the role of RNS under physiological conditions and the tumor microenvironment, which may provide some novel ideas for the development of new drugs and the treatment of diseases.

Increasing evidence suggests that hepatocellular carcinomas (HCCs) are sustained by a distinct subpopulation of self-renewing cells known as cancer stem cells (CSC). However, our understanding of their regulation is limited. Rapid reversible changes of CSC-like cells within tumors may result from the effect of biological mediators found in the tumor microenvironment. This paper aims to explore how nitrite, a key cellular modulator whose level is elevated in many tumors, affects CSC-like phenotypes of human hepatoma cells SMMC-7721 cells. The SMMC-7721 cell line was cultured under serum-free conditions to produce floating spheres. The distribution of cell cycle was analyzed by flow cytometry, the capability of cells self-renew was detected by colony-forming capabilities and spheroid-formation assay, the expression of stemness protein such as CD133, CD90 and EpCAM were determined by flow cytometry and Western blot, cell invasion was analyzed by transwell assay, and viability of SMMC-7721 parental cells and spheroids cancer cells was determined by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. Xenograft tumor models were established by subcutaneously injecting SMMC-7721 spheroids cancer cells, the transplanted tumor tissue ROS levels was detected by reactive oxygen species (ROS) test kits, the expression of HIF-1α was observed by immunofluorescence. Our results showed that the SMMC-7721 spheroid cells were enriched with CSCs properties, indicated by the ability to self-renew, increased expression of CSCs markers, and increased resistance to chemotherapeutic drugs. Additionally, SMMC-7721 parental cells and spheroids cancer cells were treated with 150 μmol·L^-1 sodium nitrite for 6 days, compared with control cells, an increased accumulation of G₀/G₁ phase cells was observable in treatment cells. Indeed, our data demonstrated that in parent cells and spheres cells that were treated with sodium nitrite for different time, the cells' ability to chemoresistance and invasion, clone-forming efficiencies and the spheres forming ability were significantly higher than that of control cells. Exposure of sodium nitrite regulated CSC-like phenotype, indicated by increased expression of known CSC markers, CD133, CD90 and EpCAM in the exposed parental cells, as well as in dormant spheroids cancer cells. Compared with the parent cells, the above effects of nitrite on the spheres cells were significantly enhanced. In vivo data also presented a more significant promotion of tumor xenograft growth from the nitrite treatment than from either of the control. Mechanistic analysis indicated that nitrite induced the upregulation of HIF-1α as well as the downregulation of ROS in the tumor microenvironment. These results suggest that nitrite increases the invasiveness of SMMC-7721 cells through up-regulation of tumor stemness.

Nitrites play multiple characteristic functions in invasion and metastasis of hepatic cancer cells, but the exact mechanism is not yet known. Cancer cells can maintain the malignant characteristics via clearance of excess mitochondria by mitophagy. The purpose of this article was to determine the roles of nitrite, reactive oxygen species (ROS) and hypoxia inducing factor 1 alpha (HIF-1α) in mitophagy of hepatic cancer cells. After exposure of human hepatocellular carcinoma SMMC-7721 cells to a serial concentrations of sodium nitrite for 24 h under normal oxygen, the maximal cell vitality was increased by 16 mg·L^-1 sodium nitrite. In addition, the potentials of migration and invasion for SMMC-7721 cells were increased significantly at the same time. Furthermore, sodium nitrite exposure displayed an increase of stress fibers, lamellipodum and perinuclear mitochondrial distribution by cell staining with Actin-Tracker Green and Mito-Tracker Red, which was reversed by N-acetylcysteine (NAC, a reactive oxygen scavenger). DCFH-DA staining with fluorescent microscopy showed that the intracellular level of ROS concentration was increased by the sodium nitrite treatment. LC3 immunostaining and Western blot results showed that sodium nitrite enhanced cell autophagy flux. Under the transmission electron microscopy (TEM), more autolysosomes formed after sodium nitrite treatment and NAC could prevent autophagosome degradation. RT-PCR results indicated that the expression levels of COXⅠ and COXⅣ mRNA were decreased significantly after sodium nitrite treatment. Meanwhile, laser scanning confocal microscopy showed that sodium nitrite significantly reduced mitochondrial mass detected by Mito-Tracker Green staining. The expression levels of HIF-1α, Beclin-1 and Bnip3 (mitophagy marker molecular) increased remarkably after sodium nitrite treatment, which were reversed by NAC. Our results demonstrated that sodium nitrite (16 mg·L^-1) increased the potentials of invasion and migration of hepatic cancer SMMC-7721 cells through induction of ROS and HIF-1α mediated mitophagy.

Recent studies have demonstrated that nitrite and ammonia levels are higher in the tumor environment, but their effects on cancer cells remains unclear. The present study was designed to determine the effects of nitrite and ammonia on tumor invasion and the role of reactive oxygen (ROS)/ornithine decarboxylase (ODC) pathway. SMMC-7721 cells were treated with sodium nitrite, ammonium chloride, sodium nitrite and ammonium chloride mixture for 24 h, the cell viability was analyzed using the MTT assay, cell invasion was analyzed with the transwell assay, the intracellular ROS levels were detected with a reactive oxygen species (ROS) test kits, the expression of intracellular ODC was examined with immunofluorescence and Western blot, the expression of matrix metallopeptidase-2(MMP-2) and MMP-9 were analyzed by Western blot. Compared with the control group, SMMC-7721 cells exhibited an increase in cell viability, invasion ability, ROS levels and ODC protein after exposure to 150 μmol·L^-1 sodium nitrite and ammonium chloride mixture for 24 h. The invasive activity was reduced by ROS scavenger N-acetycysteine (NAC) in SMMC-7721 cells. The specific ODC inhibitor difluoromethylornithine (DFMO) increased ROS levels and weakened the ability of sodium nitrite and ammonium chloride mixture in the regulation of invasion of SMMC-7721 cells. These data demonstrated that sodium nitrite and ammonium chloride mixture promote invasion of SMMC-7721 cells by enhancing ROS/ODC pathway.