ABSTRACT
Previous studies have shown that STAT3 plays a vital role in the genesis and progression of cancer. In this study, we investigated the relationship between the JAK2/STAT3 signalling pathway and germacrone-induced apoptosis in HepG2 cells. HepG2 cells were incubated with germacrone for 24 h, the protein expression of p-STAT3, STAT3, p-JAK2 and JAK2 was detected by Western Blotting, and RT-PCR was used to determine the expression of STAT3, p53, Bcl-2 and Bax at transcriptional levels. Besides that, HepG2 cells were pre-treated with AG490 or IL-6 for 2 h, and then incubated with germacrone for 24 h. The expression of p-JAK2, JAK2, p-STAT3, STAT3, p53, Bax and Bcl-2 was detected by Western blotting. The activity of HepG2 cells was tested by MTT assay. The apoptosis of HepG2 cells and levels of reactive oxygen species (ROS) were flow cytometrically measured. The results showed that germacrone exposure decreased p-STAT3 and p-JAK2 and regulated expression of p53 and Bcl-2 family members at the same time. Moreover, IL-6 enhanced the activation of the JAK2/STAT3 signalling pathway and therefore attenuated the germacrone-induced apoptosis. Suppression of JAK2/STAT3 signalling pathway by AG490, an inhibitor of JAK2, resulted in apoptosis and an increase in ROS in response to germacrone exposure. We therefore conclude that germacrone induces apoptosis through the JAK2/STAT3 signalling pathway.
ABSTRACT
Previous studies have shown that STAT3 plays a vital role in the genesis and progression of cancer. In this study, we investigated the relationship between the JAK2/STAT3 signalling pathway and germacrone-induced apoptosis in HepG2 cells. HepG2 cells were incubated with germacrone for 24 h, the protein expression of p-STAT3, STAT3, p-JAK2 and JAK2 was detected by Western Blotting, and RT-PCR was used to determine the expression of STAT3, p53, Bcl-2 and Bax at transcriptional levels. Besides that, HepG2 cells were pre-treated with AG490 or IL-6 for 2 h, and then incubated with germacrone for 24 h. The expression of p-JAK2, JAK2, p-STAT3, STAT3, p53, Bax and Bcl-2 was detected by Western blotting. The activity of HepG2 cells was tested by MTT assay. The apoptosis of HepG2 cells and levels of reactive oxygen species (ROS) were flow cytometrically measured. The results showed that germacrone exposure decreased p-STAT3 and p-JAK2 and regulated expression of p53 and Bcl-2 family members at the same time. Moreover, IL-6 enhanced the activation of the JAK2/STAT3 signalling pathway and therefore attenuated the germacrone-induced apoptosis. Suppression of JAK2/STAT3 signalling pathway by AG490, an inhibitor of JAK2, resulted in apoptosis and an increase in ROS in response to germacrone exposure. We therefore conclude that germacrone induces apoptosis through the JAK2/STAT3 signalling pathway.
Subject(s)
Humans , Apoptosis , Dose-Response Relationship, Drug , Drugs, Chinese Herbal , Hep G2 Cells , Janus Kinase 2 , Metabolism , STAT3 Transcription Factor , Metabolism , Sesquiterpenes, Germacrane , Signal TransductionABSTRACT
<p><b>OBJECTIVE</b>To compare the characterization of coronary atherosclerotic plaques in patients with unstable angina pectoris (UAP) and stable angina pectoris (SAP) by optical coherence tomography (OCT).</p><p><b>METHODS</b>OCT was performed in 47 patients (23 UAP and 24 SAP) undergoing coronary angiography. Lipid-rich plaque (defined by > or = 2 quadrants of the cross-section area), thin cap fibroatheroma (TCFA), thickness of fibrous cap, plaque rupture, calcification and thrombus visualized by OCT were compared between UAP and SAP patients.</p><p><b>RESULTS</b>OCT imaging was successfully in 44 out of 47 patients (22 UAP, 22 SAP). Proportion of lipid-rich plaques was similar between UAP and SAP groups [91% (20/22) vs. 73% (16/22), P = 0.741]. The minimum thickness of fibrous cap in the UAP group was significantly thinner than that in SAP group [(69.5 +/- 34.7) microm vs. (141.1 +/- 68.5) microm, P = 0.000] and the rate of fibrous cap erosion in the UAP group was significantly higher than that in the SAP group [59% (13/22) vs. 9% (2/22), P = 0.000]. Percents of TCFA [73% (16/22) vs. 14% (3/22), P = 0.000] and plaque rupture [50% (11/22) vs. 9% (2/22), P = 0.003] were significantly higher in UAP group compared those in SAP group. Incidence of thrombus and calcification were similar between two groups.</p><p><b>CONCLUSIONS</b>OCT imaging can clearly define plaque characterization of coronary atherosclerosis. UAP patients have thinner fibrous cap, higher incidences of fibrous cap erosion, plaque rupture and TCFA compared patients with SAP.</p>
Subject(s)
Aged , Female , Humans , Male , Middle Aged , Angina Pectoris , Diagnostic Imaging , Angina, Unstable , Diagnostic Imaging , Coronary Artery Disease , Diagnostic Imaging , Radiography , Retrospective Studies , Tomography, Optical CoherenceABSTRACT
<p><b>OBJECTIVE</b>To observe the diagnostic value of non-invasive 128-slice computed tomography coronary angiography (CTA) in comparison with invasive coronary angiography.</p><p><b>METHODS</b>128-slice CTA and invasive coronary angiography were performed in 78 unselected consecutive patients (63 patients with suspected coronary artery disease and 15 patients with previous coronary stenting, 56 males, mean age 61 +/- 10 years) and > 50% reduction of minimal lumen diameter was defined as significant coronary stenosis.</p><p><b>RESULTS</b>Fifty-eight out of 879 segments (7%) from CTA were not assessable because of irregular rhythm, vessel calcification or tachycardia. Compared with invasive coronary angiography, segment-based analysis from the 821 segments showed the sensitivity by CTA was 87%, specificity 97%, PPV 83% and NPV 97%. Four out of 22 stents implanted in 15 patients were not assessable by CTA because of poor image quality. Compared with invasive coronary angiography, the sensitivity of diagnosing in-stent restenosis by CTA was 100%, specificity 77%, PPV 63% and NPV 100% for the remaining 18 stents.</p><p><b>CONCLUSIONS</b>One hundred and twenty-eight-slice CTA has a high accuracy for detecting coronary artery disease and in-stent restenosis after coronary stenting and could be considered as a valuable noninvasive technique for screening coronary artery disease in suspected patients.</p>
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Coronary Angiography , Methods , Coronary Artery Disease , Diagnosis , Diagnostic Imaging , Coronary Stenosis , Diagnosis , Diagnostic Imaging , Tomography, Spiral Computed , MethodsABSTRACT
<p><b>OBJECTIVE</b>To evaluate coronary artery atherosclerotic plaque characteristics and changes post coronary stenting by optical coherence tomography (OCT).</p><p><b>METHODS</b>OCT images were obtained in 22 diseased coronary vessels after coronary angiography or percutaneous coronary interventions (PCI) in 20 patients and in 23 stents [7 sirolimus-eluting stents (SES) follow up at 4-29 months post stenting and 8 bare mental stents (BMS) at 4-35 months post stenting, 8 stents immediately after PCI].</p><p><b>RESULTS</b>All 22 vessels and 23 stents OCT images were successfully acquired. Two thromboses, 8 fibrous, 9 lipid-rich and 3 calcium plaques as well as 3 plaque ruptures were visualized by OCT. No significant neointimal proliferation and restenosis were found in SES stents and some struts were not covered with neointima even at 29 months post stenting. Significant neointimal proliferation on surfaces of stent struts were visualized in all 8 BMS stents and restenosis was detected in 3 BMS stents. OCT images obtained immediately after PCI showed that 3 stents were well positioned, tissue prolapse between coronary stent struts occurred in 4 stents and stent dissociation with vessel wall could be seen in 1 stent.</p><p><b>CONCLUSIONS</b>OCT imaging can clearly visualize different types of atherosclerotic plaques. By providing detailed information on plaque characteristics, this technique might help cardiologists in choosing suitable stents and guiding preventive therapy for patients with coronary heart disease.</p>