Down-regulation of HDAC6 Expression Can Influence KG1α Cell Proliferation by Inhibiting ERK Pathway / 中国实验血液学杂志

OBJECTIVE@#To study the inhibitory effect of HDAC6 on proliferation of human leukemia KG1α and to explore its mechanism by ERK signaling pathways.@*METHODS@#.The siRNA interference technology was used to inhibit the HDAC6 gene expression; the expression of HDAC6 and prateins of ERK signal pathway was detected by Western blot; the cell proliferation ability was detected by colony forming experiment and trypan blue staining; cell cycle was detected by FCM; and the expression of Ki67 was detected by immunofluorescence.@*RESULTS@#Western blot showed that HDAC6 expression was up-regulated in leukemia cell lines in comparison with the healthy volunteers and bone marrow stromal cells (P＜0.05). Knockdown of HDAC6 significantly inhibited the proliferation and colony formation ability of leukemia cells, promoted cell arrest at G/G phase. The Western blot and immunefluorescence showed that knockdown of HDAC6 suppressed the expression level of Ki67, CDK4, Cyclin D1 and enhanced the expression level of p16, p21, p-ERK (P＜0.05).@*CONCLUSION@#Knockdown of HDAC6 significantly inhibits the proliferation, arrest the cell cycle at G/G phase, and its mechanism probably relates with the activation of ERK signaling pathway.

Effect of ginsenoside Rh2(S) on apoptosis of human leukemia cell by inhibiting HDAC6 / 中草药

Objective To explore the specific mechanism of ginsenoside Rh2(S) inducing the apoptosis of leukemia cells. Methods The effect of Rh2(S) on proliferation of leukemia cells K562 and KG1a was measured by cell counting kit-8 assay (CCK-8 assay). The growth states of cells were observed under the inverted phase microscope, and cell cycle distribution, and apoptosis were determined by flow cytometry (FCM). The expression levels of HDAC6, HSP90, Akt, GSK-3β, β-catenin, and cell cycle apoptosis related proteins were ascertained by Western blotting. Results The results of CCK-8 showed that Rh2(S) had the most obvious inhibitory effect on the proliferation of leukemia cells. Rh2(S) significantly induced apoptosis and led to cell cycle arrest at G0/G1 phase of leukemia cells by FCM. While the microscope observation showed that the number of cells was decreased and normal cell morphology changed. Rh2(S) decreased the expression of Bcl-2, Cyclin D1, HDAC6, HSP90, p-Akt, and β-catenin and increased the expression of Bax, Ac-α-tubulin, and GSK-3β by Western blotting. Conclusion Rh2(S) can effectively inhibit the proliferation and promote the apoptosis of K562 and KG1a cells, its specific mechanism may relate to inhibitting the expression of HDAC6, resulting in a decline in the expression of HSP90, so as to further inhibit the activity of Akt activation of GSK-3, and finally inhibit Wnt/β-catenin pathway.

Down-regulation of HDAC6 Expression Promotes Apoptosis of Human Leukemia K562 Cells / 中国实验血液学杂志

OBJECTIVE@#To study the promoting-apoptosis effect of HDAC6 on the human leukemia cells and its mechanism.@*METHODS@#The siRNA interference technology was used to inhibit the expression of HDAC6 gene, the RT-PCR and Western blot were used to detect the expression of HDAC6 and related signal pathway proteins respectively, the flow cytometry and Hoechest staining were used to detect the apoptosis and morphology changes of K562 cells.@*RESULTS@#Compared with the periphal blood monocyte and bone marrow stromal cells of healthy volunteers, the expression level of HDAC6 in leukemia cell lines was up-regulated significantly(P<0.05); the flow cytometry and Hoechest staining showed that after interference of HDAC6 gene, the apoptosis of K562 cells increased, moreover the cell morphology was changed; the Western blot detection showed that the interfering HDAC6 increased BAX/BCL-2 ratio and cleaved caspase 3 expression, and activated the MAPK, ATK, ERK signaling pathway.@*CONCLUSION@#The interferance of HDAC6 can promote the K562 cell apoptosis, its mechanism may relate with activation of MAPK signaling pathway.

Ginsenoside Rh₂ induces apoptosis and autophagy of K562 cells by activating p38 / 中国中药杂志

To study the effect of ginseng saponin Rh₂ in inducing apoptosis of human leukemia K562 cells, and explore its mechanism from the aspect of autophagy pathway. CCK-8 assay was used to examine the growth inhibition of human leukemia cell lines K562 treated with ginsenoside Rh₂; flow cytometry (FCM) was used to detect cell apoptosis; Hoechst staining was used to observe the changes of cell morphological apoptosis; Acridine and MDC staining were used to detect the effects of the Rh₂ on autophagy; Western blot and RT-PCR were used to detect the expression levels of the proteins closely associated with autophagy and apoptosis. In order to study the effect of autophagy in proliferation and apoptosis, we used the autophagy inhibitor (3-MA).CCK-8 indicated that Rh₂ at low concentration could effectively inhibit the proliferation of leukemia cellsin dose- and time-dependent manners in K562 cells; FCM indicated that Rh₂ induced apoptosis; Hoechest staining showed that K562 cells had typical apoptotic morphological changes by treated Rh₂; Acridine and MDC staining showed that Rh₂ enhanced the green fluorescence and a large number of acidic autophagy vesicles were present; Western blot and RT-PCR results showed that Rh₂ increased the expression levels of Beclin-1, LC3A, LC3B, activated Caspase-3 and p-p38 in K562 cells; application of autophagy inhibitors(3-MA) could weaken the inhibition effect of Rh₂ on proliferation and induction effect on apoptosis in K562 cells. Ginsenoside Rh₂ inhibited the proliferation and induced apoptosis probably through activating p-p38, and inducing cell autophagy signaling pathway in K562 cells.

Ginsenoside Rh₂-induced inhibition of histone deacetylase 6 promotes K562 cells autophagy and apoptosis in vivo / 中国中药杂志

To study the in vivo inhibition effect of ginsenoside Rh₂ on humanleukemia cells, and explore its mechanism from autophagy and apoptosis aspects, human leukemia K562 cells allograft tumor models were applied, and after administration of ginsenosides Rh₂ by gavage, the tumor diameter, volume and inhibitory rate were measured, and the anti-tumor activity of ginsenosides Rh₂ was observed. The levels of HAT and HDAC in tumor tissues were detected by chemical colorimetry assay, and expressions of HDAC1, HDAC2, HDAC3, HDAC4, HDAC5 and HDAC6 were detected by Western blotting assay. The expression levels of vital genes closely associated with autophagy and mRNA expressions of HDAC6 and Hsp90 were detected by Real time-PCR. HE staining was used to observe apoptosis, and immunohistochemistry was used to detect the protein expressions of HDAC6, Hsp90 and activated caspases 3. The results showed that ginsenoside Rh₂ could inhibit the growth of k562 cells allograft tumor, with a tumor inhibition rate up to 53.10%. Ginsenoside Rh₂ could significantly decrease HDAC activity and decrease the expressions of HDAC1, HDAC2 and HDAC6, and inhibit the expressions of HDAC6 and HSP90, increase the expressions of vital autophagy genes (beclin-1, LC3A and LC3B). Histopathological results showed that ginsenosides Rh₂ could significantly increase the tumor apoptosis. Therefore, ginsenoside Rh₂ had good anti-tumor effect in vivo, and the mechanism maybe associated with regulating autophagy and apoptosis through HDAC6 and Hsp90 pathways and inhibiting the in vivo proliferation of tumor cells.

Effect of ginseng polysaccharide-induced wnt/beta-catenin signal transduction pathway on apoptosis of human nasopharyngeal cancer cells CNE-2 / 中国中药杂志

<p><b>OBJECTIVE</b>To observe the effect of ginseng polysaccharide (GPS) on the proliferation and apoptosis of human nasopharyngeal cancer cells CNE-2, and discuss the possible mechanism.</p><p><b>METHOD</b>The effect of GPS on the growth of CNE-2 cells was observed by CCK8 assay. CNE-2 cells in the logarithmic phase were collected and processed respectively with different concentrations (0, 0. 1, 0. 2, 0. 3. 0. 4 g L-1) of GPS for 48 h. The flow cytometry was used to detect its induction effect on CNE-2 cell apoptosis. Hoechst-33258 cell staining and electron microscope were used to observe the morphological changes of cells. The beta-catenin mRNA expression was detected by Real-time PCR. The protein localizations and expressions of beta-catenin and TCF4 were tested by the immunofluorescence staining. The expressions of beta-catenin, Bcl-2 and Bax proteins were detected by Western blot.</p><p><b>RESULT</b>CCK8 assay results showed that GPS could remarkably inhibit the proliferation of CNE-2 cells, with dose-time dependence. IC50 of cells induced with GPS for 48 h was 0. 39 g L-1. After being processed with GPS with concentrations of 0.1, 0. 2, 0. 3, 0. 4 g L-1 for 48 h, the cell apoptosis rates of human nasopharyngeal cancer cells CNE-2 were (5. 69 +/- 0. 29)% , (10. 3 +/- 0. 63)% , (15. 4 +/- 0. 74 ) % and (35. 7 +/- 1. 86)% , respectively. Significant difference was observed compared with the control group (2. 08 +/- 0. 11) % (P <0. 05). The results of Hoechst-33258 staining showed the characteristics of cell apoptosis. Under the electron microscope, apoptosis bodies could be observed among CNE-2 cells induced with GPS with the concentration of 0. 4 g L -1 for 48 h. The results of Real-time PCR showed a significant reduction in beta-catenin mRNA expression. The results of laser confocal microscopy revealed notable decrease of beta-catenin and TCF4 expression in nucleus and transfer from nucleus to cell membranes in beta-catenin expression areas after being processed with GPS for 48 h. Western blot showed significant decrease in the expressions of beta-catenin and anti-apoptosis protein Bcl-2, with an increasing expression in apoptosis-promoting protein Bax (P <0. 05).</p><p><b>CONCLUSION</b>GPS could significantly inhibit the proliferation of CNE-2 cells and promote thier apoptosis. The obstruction of Wnt/beta-catenin signaling pathway may be an important mechanism for GPS to induce the apoptosis of human nasopharyngeal cancer cells CNE-2.</p>