ObjectiveTo identify genes associated with resistance to programmed cell death protein 1 (PD-1) inhibitors in colorectal cancer and elucidate their underlying mechanisms using bioinformatics approaches. MethodsGenes expression datasets were downloaded from the Gene Expression Omnibus (GEO) database to screen hypoxia-related genes (HRGs) and differentially expressed genes (DEGs). The intersection of HRGs and DEGs was defined as hypoxia-related differentially expressed genes (HDGs). The gene expression data of patients with colorectal cancer from The Cancer Genome Atlas (TCGA) were analyzed using Pearson correlation to identify the PD-1-related genes, further the STRING analysis (minimum interaction score was greater than 0.7) and Cytoscape were subsequently employed to screen the key PD-1-related genes. The relation between the screened key PD-1-related genes and the prognosis of colorectal cancer patients was analyzed to screen out the target genes. The real-time fluorescence reverse transcription quantitative polymerase chain reaction was used to analyze the expression of the target genes in the cancer tissues and their corresponding adjacent tissues of 20 patients with colorectal cancer. The Kaplan-Meier Plotter database and the ROC Plotter database were used to analyze the relation between the high and low expression of the target genes and the prognosis in different patients. The significance level was set as α=0.05. ResultsA total of 651 HRGs and 329 DEGs were screened out. By taking the intersection of these two sets, 37 HDGs were obtained for subsequent analysis. Through Pearson correlation analysis, 25 key PD-1-related genes were screened out and 10 and 14 key PD-1-related genes were screened out by the MCC algorithm and the MCODE algorithm respectively. By taking the intersection of these three sets, 3 key PD-1-related genes were obtained, then survival analysis, the Aurora kinase A (AURKA) gene was finally screened out as the target gene. The expression level of the AURKA gene in the pan-cancer patients who responded to PD-1 inhibitor treatment was significantly higher than that in non-responders (P＜0.001), and was significantly lower in the six colorectal cancer cells treated with hypoxia than in six colorectal cancer cells treated with normoxia (P＜0.001). The AURKA expression in the colorectal cancer tissues was significantly higher than that in the corresponding adjacent colorectal tissues (P=0.008). The overall survival of pan-cancer patients with high AURKA expression was better than that of those with low AURKA expression [HR (95%CI)=0.67 (0.49, 0.93), P=0.015]. Among the colorectal cancer patients with MMR deficiency, the patients with low AURKA gene expression had worse overall survival [HR (95%CI)=2.596 (1.028, 6.332), P=0.043] and recurrence-free survival [HR (95%CI)=4.201 (1.092, 16.150), P=0.037] as compared with those with high AURKA gene expression. The low AURKA expression was associated with significantly worse overall survivals in the colorectal cancer patients harboring wild-type or mutant TP53, BRAF, and KRAS as compared with high AURKA expression (P＜0.05), while no statistically significant difference was found in the overall survival of the normal MMR patients between with high AURKA expression and low AURKA expression (P=0.307). ConclusionThe results of this bioinformatics analysis suggest that hypoxia down-regulated AURKA expression, and low AURKA expression is associated with worse prognosis in colorectal cancer patients, and worse reactivity and prognosis in patients treated with PD-1 inhibitors.
Objective To investigate the effect of ginkgolide B (GB) on cysteinyl aspartate specific proteinase-3 (Caspase-3)/chromosome 10 deletion phosphatase-tension protein homologue (PTEN)/protein kinase B (Akt) pathway and cell proliferation and apoptosis in hypoxia/reoxygenation cardiomyocytes. Methods H9C2 cells were cultured in vitro. A control group was cultured in serum-free DMEM high glucose medium at 37°C and 5% CO2 for 28 hours. The remaining groups were prepared with hypoxia/reoxygenation models. A GB low-dose group and a GB high-dose group were treated with GB pretreatment with final concentration of 50 μmol/L and 200 μmol/L respectively at 1 h before hypoxia/reoxygenation. A carvedilol group was treated with carvedilol of a final concentration of 10 μmol/L at 1 h before hypoxia/reoxygenation. The proliferation and apoptosis of H9C2 cells were detected, and the levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), reactive oxygen species (ROS), PTEN, Akt, phosphorylated Akt (p-Akt) and Caspase-3 in H9C2 cells were also detected. Results Compared with the control group, the proliferation rate of H9C2 cell, and the levels of PTEN, Akt and p-Akt in other groups decreased, and the apoptosis rate, and the levels of LDH, MDA, ROS and Caspase-3 increased (P<0.05). Compared with the hypoxia/reoxygenation group, the proliferation rate of H9C2 cell, and the levels of PTEN, Akt and p-Akt in all GB dose groups and the carvedilol group increased; the apoptosis rate, and the levels of LDH, MDA, ROS and Caspase-3 decreased, and the effect of GB was in a dose dependent manner; however, the effect of GB was not as strong as carvedilol (P<0.05). Conclusion GB can inhibit H9C2 cell apoptosis and promote H9C2 cell proliferation by activating Caspase-3/PTEN/Akt pathway.
Objective To investigate the effect of angiopoietin-like protein 3 (ANGPTL3) on lipid metabolism in patients with obstructive sleep apnea (OSA). Methods A total of 59 OSA patients and 20 healthy controls from the First Affiliated Hospital of Zhengzhou University between May 2023 and February 2024 were included in the study. All participants underwent overnight polysomnography (PSG). Based on the apnea-hypopnea index (AHI), the OSA patients were divided into a mild group and a moderate-to-severe group. Morning blood samples were collected after an 8-hour fast to measure lipid profiles and ANGPTL3 levels. Statistical analyses were performed using SPSS 25.0 software. Results The levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and ANGPTL3 were significantly higher, while high-density lipoprotein cholesterol (HDL-C) was significantly lower in the OSA group compared with the control group (P<0.05). ANGPTL3 level was higher in the moderate-to-severe OSA group than that in the mild OSA group and the control group, and higher in the mild OSA group than that in the control group (P<0.05). In the severe hypoxemia group, ANGPTL3 level was significantly higher than that in the mild-to-moderate hypoxemia group (P<0.05). The ANGPTL3 level was also significantly higher in the hyperlipidemia group compared wiht the non-hyperlipidemia group (P<0.05). In the OSA group, ANGPTL3 was positively correlated with TC, TG, percentage of cumulative time with oxygen saturation below 90% in total sleep time (T90) and oxygen desaturation index (ODI), and negatively correlated with lowest arterial oxygen saturation (LSaO2) and mean arterial oxygen saturation (MSaO2). After adjusting for relevant confounding factors, logistic regression analysis indicated that ANGPTL3 might be a potential independent risk factor for OSA, with an odds ratio of 1.021 (95%CI 1.002 - 1.040). Conclusions The level of ANGPTL3 is elevated in OSA patients. The elevation of blood lipid levels in OSA patients may be associated with chronic intermittent hypoxia-induced regulation of ANGPTL3 levels.
ObjectiveTo investigate the expression and correlation of hypoxia inducible factor 1α (HIF-1α) and autophagy related molecules (Beclin1 and LC3B) in rat nucleus pulposus cells under hypoxia in vitro.MethodsThe nucleus pulposus cells were extracted from the nucleus pulposus of healthy adult Sprague Dawley rats and passaged. The 3rd generation cells were identified by HE staining and collagenase type Ⅱ immunofluorescence staining and randomly divided into 4 groups. The cells in group A were cultured for 8 hours under normal oxygen condition (37℃, 5%CO2, 20%O2); the cells in group B were cultured for 8 hours under hypoxia condition (37℃, 5%CO2, 1%O2); the cells in group C were transfected with HIF-1α-small interfering RNA and cultured for 8 hours under hypoxia condition; and the cells in group D were cultured with autophagy inhibitor 3-MA for 8 hours under hypoxia condition. Western blot and real-time fluorescence quantitative PCR (qRT-PCR) were used to detect the expressions of HIF-1α and autophagy related molecules (Beclin1 and LC3B) in all groups.ResultsHE staining of the 3rd generation nucleus pulposus cells showed that the cytoplasm was light pink and the nucleus was blue black, and the collagenase type Ⅱ immunofluorescence staining was positive. Western blot and qRT-PCR results showed that the relative expressions of HIF-1α, Beclin1, and LC3B proteins and genes in group B were significantly higher than those in group A (P<0.05); the relative expressions of HIF-1α, Beclin1, and LC3B proteins and genes in group C were significantly lower than those in group B (P<0.05). There was no significant difference in the relative expression of HIF-1α protein and gene between groups B and D (P>0.05); while the relative expressions of Beclin1 and LC3B proteins and genes in group D were significant lower than those in group B (P<0.05).ConclusionHypoxia can induce the expressions of HIF-1α and autophagy related molecules (Beclin1 and LC3B) in rat nucleus pulposus cells, and HIF-1α in rat nucleus pulposus cells under hypoxia is related to the expression of autophagy related molecules, that is, down-regulation of HIF-1α can significantly reduce the expression of autophagy related molecules, while the down-regulation of autophagy levels under hypoxia has no or little effect on the expression of HIF-1α.
ObjectiveTo detect the expression level of phosphate and tension homolog deleted on chromsome ten(PTEN) and its downstream signal molecules phosphorylated protein kinase B (p-AKT) in liver cells of rats during intermittent hypoxia,to investigate the effect of PTEN and p-AKT of liver cells on insulin resistance which intermittent hypoxia is relevant. MethodsA total of 24 healthy male SD rats were selected and divided into 3 groups randomly,ie.CIA (chronic intermittent air) group,CIH4 (chronic intermittent hypoxia for 4 weeks) group,and CIH8 (chronic intermittent hypoxia for 8 weeks) group. The fasting blood glucose,fasting insulin,PTEN and p-AKT expressions in the liver cells were detected. The insulin resistance was evaluated systematically by the insulin sensitive index (ISI) and homeostasis model assessment of insulin resistance (HOMA-IR). Average gray value was used to represent the protein expressions of PTEN and p-AKT. ResultsCompared with CIA group,the decline of ISI in CIH4 group and CIH8 group was significant (P<0.05). Furthermore,the decline in CIH8 group was more significant than that in CIH4 group (P<0.05). Compared with CIA group,the rise of HOMA-IR in CIH4 and CIH8 groups was statistically significant (P<0.05). In addition,the rise in CIH8 group was more significant than that in CIH4 group (P<0.05). Compared with CIA group,there was a significant rise in the protein expressions of PTEN in CIH4 and CIH8 groups (P<0.05). Compared with CIH4 group,the rise of the protein expressions of PTEN in CIH8 group was still statistically significant (P<0.05). Compared with CIA group,there was a significant decline in the protein expressions of p-AKT in CIH4 and CIH8 groups (P<0.05). Compared with CIH4 group,the decline of protein expression of p-AKT in CIH8 group was still of statistical significance (P<0.05). There was a significantly increasing trend for the expression of PTEN in the liver cells of rats with intermittent hypoxia along with the decline of ISI and rise of HOMA-IR. The expression increased significantly with the longer duration of intermittent hypoxia. The expression of p-AKT in liver cells of rats with intermittent hypoxia decreased along with the decline of ISI and rise of HOMA-IR. Furthermore,the decline tendency was more significant with the long duration of intermittent hypoxia. ConclusionThe fasting blood glucose of rats and insulin level increase due to the chronic intermittent hypoxia,resulting in the insulin resistance. The degree of insulin resistance increases with the longer duration of intermittent hypoxia. The expression of PTEN protein increases with intermittent hypoxia,and that of p-AKT protein decreases,which is obviously correlated with ISI and HOMA-IR. It is indicated that the PTEN protein possibly play an important role in the mechanism of insulin resistance for rats with intermittent hypoxia.
Objective： To observe the effect of estrogen on the expr ession of pigment epithelium derived factor (PEDF) in cultured retinal Muuml;ller cells under the anoxic condition． Methods：After the anoxic retinal Muuml;ll er cells were tre ated with estrogen (E2) with the concentration of 10-6、10-5 and 10-7 mmol/L, t he level of expression of PEDF mRNA and the protein was detected by reverse tran scriptionpolymerase chain reaction and Western blotting analysis. Results：Th e expression of PEDF mRNA and protein decreased 24 hours after anoxia. E2 with t he concentration of 10-5 and 10-6 mmol/L inhibited the decrease of expression of PEDF mRNA and protein induced by anoxia, which related to the concentration of E2． Conclusion：strogen can regulate the expression of PEDF, which ma y play an important role in the regulation of retinal neovascularization．
ObjectiveTo study the influence of hemin on blood pressure of intermittent hypoxic rats and investigate the mechanism of hypertension caused by intermittent hypoxia.MethodsTwenty-four male SD rats were randomly divided into a hemin group, an intermittent hypoxia group (IH group) and a normal group. Thirty minutes after intraperitoneal injection of hemin, the rats in the hemin group were exposed to intermittent normobaric hypoxic environment (8 h/d). The rats in the IH group were intraperitoneal injected with normal sodium and then exposed to the same environment (8 h/d). The rats in the normal group were intraperitoneal injected with normal sodium and placed in the glass box. The three groups were bred in the same condition. Thirty-five days later, the mean carotid artery pressure (mCAP) of the rats was measured and their plasma carbon monoxide (CO) level was measured by Chalmer’s method. Reverse transcription polymerase chain reaction was performed to detect the levels of heme oxygenase-1 (HO-1) mRNA expression in lung, liver, spleen, kidney and other organs. The expression of HO-1 protein in the organs was detected by immunohistochemistry.ResultsThe mCAP in the IH group was significantly higher than the hemin group and the normal group (P<0.05), and was higher in the hemin group than the normal group (P<0.05). The concentration of plasma CO in the hemin group was higher than the IH group and the normal group (P<0.05). There was no significant difference in plasma CO between the IH group and the normal group (P>0.05). The expression of HO-1 mRNA of lung, liver, spleen and kidney in the hemin group and the IH group was higher than the normal group (P<0.05), and was higher in the hemin group than the IH group (P<0.05). The relationship between mCAP and HO-1 mRNA showed a curvilinear trend. The quadratic curve fitting equation was Y=39.715+446.640X-334.353X2.ConclusionsIntermittent hypoxia can cause hypertension in rats. The HO-1 expression is increased in hypoxic rats, but the plasma CO does not increase significantly. As an inducer of HO-1, hemin can increase the expression of HO-1 and CO in hypoxic rats, then lower their blood pressure to some extent.
ObjectiveTo explore the effects of hypoxia inducible factor-1 alpha (HIF-1α) on the reverse differentiation of hepatocellular carcinoma cells into liver cancer stem cells, and the maintenance of malignant biological behavior in hypoxic environment.MethodsCD133-negative cells in HepG2 cells were separated by immunomagnetic beads and divided into two groups. The cells of siRNA group were transfected with siRNA-HIF-1α to silence the expression of HIF-1α gene, while cells of the blank control group did not transfect any siRNA fragments. The two groups of cells were cultured under normal and hypoxic conditions respectively. MTT, cloning and Transwell chamber experiments were used to detect the proliferation and invasion ability of cells. Western blot and real-time PCR (RT-PCR) were used to detect the expressions of HIF-1α, CD133, CD90, and CD44 protein and mRNA in cells.ResultsMTT results showed that the cell proliferation rate increased with the prolongation of hypoxia in four groups. Compared with the blank control group at 24, 32, 40, and 48 hours, the cell proliferation rate decreased significantly after siRNA-HIF-1a transfection, on both two kinds of cultured conditions (P<0.05). The results of plate cloning experiment showed that the number of cell-forming clones increased significantly after hypoxic culture (there were significant differences between the transfected normoxic group and transfected hypoxic group, blank control normoxic group and blank control hypoxic group, P<0.05); and the formation of transfected hypoxic condition group at the same time of hypoxia was also significant (P<0.05). The number of clones were significantly less than that of the blank control group at the hypoxic condition (P<0.05). Transwell lab experiment showed that after hypoxic culture, the number of cells migrated to the inferior chamber in the transfection group was significantly reduced compared with that of the blank control group (P<0.05). Western blot and RT-PCR results showed that the expression levels of HIF-1α protein and tumor stem cell markers (CD133, CD90, and CD44 protein) in the blank control hypoxic condition group were significantly higher than those in the other three groups (P<0.05); after siRNA-HIF-1a transfection, HIF-1α mRNA and tumor stem cell markers mRNA (CD133, CD90, and CD44 mRNA) in the transfected hypoxic condition group were significantly lower than those in the transfected normal condition group and the blank control normal condition group (P<0.05).ConclusionsIn hypoxia environment, HIF-1α can promote hepatocellular carcinoma cells to differentiate into liver cancer stem cells and enhance their malignant biological behavior.
Objective To observe the expression of vascular endothelial growth factor receptor-1 (VEGFR-1) and VEGFR-2 in hypoxic chorioretinal endothelial cells of monkeys (RF/6A), and to evaluate the effect of minocycline. Methods RF/6A was cultured and divided into four groups: control group, hypoxia group, hypoxia and low dose of minocycline group (0.5 mu;mol/L), hypoxia and medium dose of minocycline group (5 mu;mol/L), and hypoxia and high dose of minocycline group (50 mu;mol/L). Real-time reverse transcriptionpolymerase chain reaction (RT-PCR) and immunohistopathological staining were used to measure the mRNA and protein expression of VEGFR-1 and VEGFR-2, respectively. Results RT-PCR showed that the expression of VEGFR-1 mRNA did not vary significantly between groups (F 24 h=0.17,F 48 h=1.53,F72 h=2.04;P＞0.05). Compared with hypoxia group, the expression of VEGFR-2 mRNA in all minocycline treated groups were significantly downregulated (low minocycline, medium minocycline, high minocycline: t=4.69, 20.16, 17.12; P＜0.001). The immunohistopathological study showed the cells with positive staining of VEGFR-1 can be observed in all groups, and the staining was relatively weak and mainly located in cell membrane and cytoplasm. The optical density value analysis showed that the protein expression of VEGFR-1 did not vary significantly between groups at all time points（F 24 h=0.251,F 48 h=0.340,F72 h=0.589;P＞0.05）. The VEGFR-2 positive staining cells were also observed in all groups, and the staining was relatively high. Brown staining particles of VEGFR-2 were observed in the cell membrane with minor staining particles in cytoplasm. The staining density of VEGFR-2 was significantly higher in hypoxia group than control group. Compared with the hypoxia group, the protein expression of VEGFR-2 in minocycline treated groups was significantly lower（F 24 h=19.147,F 48 h=14.893,F72 h==11.984; P＜0.05). Conclusion The expression of VEGFR-2 is upregulated in RF/6A, and minocycline somewhat shows an inhibition effect.
Objective To investigate the effect of hypoxia on expressions of erythropoietin（EPO）mRNA and protein in retinal Muuml;ller cells cultured in vitro. Methods Retina tissues from the new-born Wistar rats were dissected into cell suspension after digested by pancreatin.Muuml;ller cells were separated and purified by mechanical concussion and blowing and striking method.The expression of EPO mRNA and protein under the condition of hypoxia was detected by semi-quantitative reverse transcriptase（RT）-polymerase chain reaction（PCR）and immunocytochemical method. Results Retinal Muuml;ller cells were cultured successfully，95% of which were positively stained by glial fibrillary acidic protein（GFAP）.Positively stained EPO protein was located in the cytoplasm and protuberance.The expression of EPO mRNA and protein was faint in the normal retinal Muuml;ller cells，but increased obviously and time-dependently after hypoxia. Conclusion Expression of EPO mRNA and protein increases in Muuml;ller cells after hypoxia，which may be one of the protective factors for the nerves in anoxic retinopathy. (Chin J Ocul Fundus Dis, 2006, 22: 196-199)