scholarly journals An Immunomodulatory Protein (Ling Zhi-8) from aGanoderma lucidumInduced Acceleration of Wound Healing in Rat Liver Tissues after Monopolar Electrosurgery

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Hao-Jan Lin ◽  
Yushan-Sophie Chang ◽  
Li-Hsiang Lin ◽  
Chiung-Fang Haung ◽  
Chia-Yu Wu ◽  
...  
Keyword(s):  
Wound Healing ◽  
Western Blot ◽  
Rat Liver ◽  
Blot Analysis ◽  
Liver Tissue ◽  
Caspase 3 ◽  
Dapi Staining ◽  
Monopolar Electrosurgery ◽  
Immunomodulatory Protein ◽  
Liver Tissues

The purpose of this study was to investigate the effect of an immunomodulatory protein (Ling Zhi-8, LZ-8) on wound healing in rat liver tissues after monopolar electrosurgery. Animals were sacrificed for evaluations at 0, 3, 7, and 28 days postoperatively. It was found that the wound with the LZ-8 treatment significantly increases wound healing. Western blot analysis clearly indicated that the expression of NF-κB was decreased at 3, 7, and 28 days when liver tissues were treated with LZ-8. Moreover, caspase-3 activity of the liver tissue also significantly decreases at 7 and 28 days, respectively. DAPI staining and TUNEL assays revealed that only a minimal dispersion of NF-κB was found on the liver tissue treated with LZ-8 at day 7 as compared with day 3 and tissues without LZ-8 treatment. Similarly, apoptosis was decreased on liver tissues treated with LZ-8 at 7 days when compared to the control (monopolar electrosurgery) tissues. Therefore, the analytical results demonstrated that LZ-8 induced acceleration of wound healing in rat liver tissues after monopolar electrosurgery.

scholarly journals Effects and Mechanism of Oxymatrine Combined with Compound Yinchen Granules on the Apoptosis of Hepatocytes through the Akt/FoxO3a/Bim Pathway

2022 ◽  
Vol 2022 ◽  
pp. 1-11
Author(s):  
Xian Zhang ◽  
Jiajia Ge ◽  
Xuejuan Zhu ◽  
Haifeng Zhang ◽  
Yuanzi Wang ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Western Blot ◽  
Liver Failure ◽  
Acute Liver Failure ◽  
Rat Liver ◽  
Caspase 3 ◽  
Normal Group ◽  
Model Group ◽  
Apoptosis Rate ◽  
Liver Tissues

The aim of the present study was to investigate the effects and mechanism of oxymatrine (OMT) combined with compound yinchen granules (CYG) on the apoptosis of hepatocytes through the Akt/FoxO3a/Bim pathway in rats with acute liver failure. The rat model of acute liver failure was established using lipopolysaccharide/D-galactosamine (LPS/D-GalN). The expression of proteins in rat liver tissues was detected by western blot analysis. The mRNA expression of FoxO3a, Bim, Bax, Bcl-2, and caspase-3 in rat liver tissues was detected by RT-qPCR. The apoptosis rate of rat hepatocytes was determined by flow cytometry. Western blots showed that when compared with the normal group, the expression of p-Akt and p-FoxO3a in the model group was decreased ( P < 0.05 ), while the expression of Bim was increased ( P < 0.01 ). Compared with the model group, the expression of p-Akt and p-FoxO3a in the OMT group and the OMT combined with CYG groups was increased ( P < 0.05 or P < 0.01 ), while the expression of Bim was decreased ( P < 0.05 ). The Bax/Bcl-2 ratio and caspase-3 protein expression in the model group were significantly higher than those in the normal group ( P < 0.01 ). The Bax/Bcl-2 ratio and the expression of caspase-3 protein in the OMT group and the OMT combined with CYG groups were significantly lower than those in the model group ( P < 0.01 ). The results of RT-qPCR were consistent with those of western blot. The results of flow cytometry showed that the apoptosis rate of hepatocytes in the OMT group and the OMT combined with CYG groups was significantly lower than that in the model group ( P < 0.05 or P < 0.01 ). We concluded that LPS/D-GalN can induce apoptosis of hepatocytes in rats with acute liver failure through the Akt/FoxO3a/Bim pathway. OMT combined with CYG inhibits apoptosis of hepatocytes in rats with acute liver failure via the Akt/FoxO3a/Bim pathway.

scholarly journals DIAPH1 Is Upregulated and Inhibits Cell Apoptosis through ATR/p53/Caspase-3 Signaling Pathway in Laryngeal Squamous Cell Carcinoma

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Jiechao Yang ◽  
Liang Zhou ◽  
Yanping Zhang ◽  
Juan Zheng ◽  
Jian Zhou ◽  
...  
Keyword(s):  
Squamous Cell Carcinoma ◽  
Western Blot ◽  
Cell Carcinoma ◽  
Squamous Cell ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Molecular Mechanisms ◽  
Caspase 3 ◽  
Laryngeal Squamous Cell Carcinoma ◽  
Poor Overall Survival

Cancer bioinformatics has been used to screen possible key cancer genes and pathways. Here, through bioinformatics analysis, we found that high expression of diaphanous related formin 1 (DIAPH1) was associated with poor overall survival in head and neck squamous cell carcinoma and laryngeal squamous cell carcinoma (LSCC). The effect of DIAPH1 in LSCC has not been previously investigated. Therefore, we evaluated the expression, function, and molecular mechanisms of DIAPH1 in LSCC. Immunohistochemistry and western blot analysis confirmed the significant upregulation of DIAPH1 in LSCC. We used DIAPH1 RNA interference to construct two DIAPH1-knockdown LSCC cell lines, AMC-HN-8 and FD-LSC-1, and validated the knockdown efficiency. Flow cytometry data showed that DIAPH1 inhibited apoptosis. Further, western blot analysis revealed that DIAPH1 knockdown increased the protein levels of ATR, p-p53, Bax, and cleaved caspase-3, -8, and -9. Thus, DIAPH1 is upregulated in LSCC and may act as an oncogene by inhibiting apoptosis through the ATR/p53/caspase-3 pathway in LSCC cells.

Abstract 255: Cytoprotective Effects of Erythropoietin and Erythropoietin-derivatives in Ischaemic Human Myotubes and the Role of Pi3k/akt Signalling Pathway

2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Rebekah Sian Hwee Yu ◽  
Daryll Baker ◽  
David Abraham ◽  
Janice Tsui
Keyword(s):  
Skeletal Muscle ◽  
Western Blot ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Caspase 3 ◽  
Signalling Pathway ◽  
Critical Limb Ischaemia ◽  
Human Myotubes ◽  
Muscle Biopsies

Objectives Erythropoietin (Epo) has tissue-protective effects in response to injury, acting through the EpoR-βcR heteroreceptor. We have previously demonstrated the presence and interaction of the EpoR and βcR in human skeletal muscle. Here we aim to investigate the potential cytoprotective effects of Epo and an Epo-derivative (ARA-290) in a human in vitro model of skeletal muscle and establish a potential downstream signalling pathway utilised in protecting cells from apoptosis (including Jak-2, PI3k/Akt, NFkB). Methods Gastrocnemius muscle biopsies were obtained from patients with critical limb ischaemia and control samples were obtained from non-ischaemic patients. Human myoblasts were isolated from muscle biopsies, cultured, and allowed to differentiate into myotubes in order to investigate the cytoprotective effects of Epo and ARA-290 on myotubes subjected to simulated ischaemia. The PI3k inhibitors, LY294002 and wortmannin, were then used to determine the role of PI3k/Akt pathway in mediating cytoprotection. Following this, inhibitors against the upstreatm (Jak-2) and downstream (NFkB) molecules were also investigated. Western blot analysis, using the pro-apoptotic marker cleaved caspase-3 was performed and compared with levels of Akt and phosphorylated-Akt, using western blot analysis. Results Exogenous administration of Epo and ARA-290 were able to ameliorate the ischaemia-induced apoptosis on isolated human myotubes as shown by a significant reduction in cleaved caspase-3 expression. Addition of all inhibitors, to ARA-290 or Epo pre-treated cells, abolished the reduction in apoptosis. Conclusion The ability of ARA-290 to attenuate apoptosis in human myotubes undergoing ischaemic insult suggests a potential role in tissue protection in skeletal muscle injury. We propose that the PI3k/Akt signalling pathway is involved in mediating this cytoprotection.

Dexmedetomidine Suppressing Apoptosis to Release Rats’ Liver Ischemia-Reperfusion Injury

2021 ◽  
Vol 11 (8) ◽  
pp. 1536-1542
Author(s):  
Zhao Hai-Fan ◽  
Li Chong ◽  
Hu Zhi-Duo ◽  
Chen Hong ◽  
Jiang Tao ◽  
...  
Keyword(s):  
Western Blot ◽  
Liver Tissue ◽  
Caspase 3 ◽  
Sham Group ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Pathological State ◽  
Inhibitory Effects ◽  
Hepatic Ischemia ◽  
Hepatic Ischemia Reperfusion

Purpose: Explore the dexmedetomidine’s therapeutic impact on hepatic ischemia-reperfusion (I/R) injury and the related principle. Methods: The work established the rats’ liver I/R model. Liver tissues’ pathological state from each rat was evaluated by HE staining. ELISA was utilized to confirm the activity of MDA and SOD in the liver tissue, AST in the serum, and the ALT’s concentration. The apoptotic state of liver tissue was detected by TUNEL assay. Bcl-2, Caspase-3, HO-1, and BAX’s expressions of each rat’s liver tissue had been confirmed through immunohistochemistry and western blot. Results: Rats’ liver injury from I/R group and DEX+A group was rat’s liver tissue had been confirmed through immunohistochemistry and western blot. severer than that from Sham group in terms of HE staining and ELISA. The injured tissue has been improved by the introduction of Dexmedetomidine. The TUNEL, Immunohistochemistry and Western Blot results indicated that the high apoptotic rate in I/R model was inhibited using Dexmedetomidine. However, the inhibitory effects were reversed by the co-administration of Atipamezole. Conclusion: Dexmedetomidine suppressed apoptosis to alleviate rats’ hepatic ischemia-reperfusion injuries.

Pan-BCL-2 Family Small Molecule Inhibitor GX015-070 (GeminX, Inc.) Exhibits Single Agent Cytotoxicity, Is Synergistic with Select Anti-Leukemia Cytotoxic Agents, and Induces Apoptosis in Cell Lines with t(4;11)(q21;q23) Translocations.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3368-3368 ◽  
Author(s):  
Jessicca M. Rege ◽  
Blaine W. Robinson ◽  
Manish Gupta ◽  
Jeffrey S. Barrett ◽  
Peter C. Adamson ◽  
...  
Keyword(s):  
Cell Death ◽  
Western Blot ◽  
Family Member ◽  
Cell Lines ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Caspase 3 ◽  
Single Agent ◽  
Cytotoxic Agents ◽  
Response Surface Modeling

Abstract Background: Leukemias with MLL translocations, especially t(4;11), often are resistant to common chemotherapeutic agents, which may be due to abnormal apoptosis regulation. Pro- and anti-apoptotic BCL-2 family member interactions govern initiation of the intrinsic apoptosis pathway. GX015-070, which currently is in Phase I/IIA clinical trials, mimics the BH3 domain on pro-apoptotic BCL-2 family proteins and can bind the BH3 binding pocket of anti-apoptotic BCL-2 family members and modulate apoptosis. We performed comprehensive protein expression profiling of BCL-2 family member proteins and evaluated in vitro activity and mechanism of action of GX015-070 in cell lines with t(4;11). Methods: Baseline expression of BCL-2 family proteins was determined by Western blot analysis. Cytotoxicity was assessed by MTT after a 3 day exposure of RS4:11, SEM-K2 and MV4-11 cells in log phase growth to single agent GX015-070 at concentrations from 5 nM to 7.5 μM. Combined effects of fixed-concentration GX015-070 with cytotoxic agents over a range of concentrations were assayed by MTT, and the results were analyzed by pharmacostatistical response surface modeling. Disruption of specific pro- and anti-apoptotic BCL-2 family member interactions was investigated by co-immunoprecipitation/Western blot analysis. Flow cytometry and/or Western blot analysis of Caspase-3 activation, and a FACS TUNEL assay, were used to assess apoptosis in GX015-070 treated and untreated cells. Results: The three cell lines had similar baseline levels of expression of BCL-2 family proteins. BCL-2 and BAX were most abundant followed by PUMA, BAK, BCL-XL, BIM-EL, MCL-1, BIK and NOXA. Results of assays of GX015-070 activity and mechanism of action are in shown in the table. Conclusions: These data indicate that GX015-070 has potent cytotoxic activity in cell lines with t(4;11) as a single agent and that the cytotoxicity results from apoptosis. Response surface modeling in RS4:11 cells suggested ability to achieve effective doses with GX015-070 combined with cytosine arabinoside (Ara-C), dexamethasone (Dex) or doxorubicin (ADR) that are lower than projected from the single agents, but synergy was not suggested when GX015-070 was combined with etoposide, methotrexate or 6-thioguanine. The co-IP experiments give proof of principle that GX015-070 disrupts pro- and anti-apoptotic BCL-2 family protein interactions in cell lines with t(4;11). Additional pre-clinical experiments directed at overcoming drug resistance from abnormal cell death regulation in leukemias with t(4;11) using GX015-070 are in progress. These studies provide a framework to understand the cell death/survival machinery in primary leukemias with t(4;11) translocations more completely and manipulate that machinery to achieve better treatments. GX015-070 Activity and Mechanism Cell Line Single Agent Activity Synergy Inhibition Caspase-3 Activation TUNEL RS4:11 IC50=43.5 nM Ara-C, Dex, ADR Mcl1:Bak; Bcl2:Bak + + SEM-K2 IC50=156 nM In progress Mcl1:Bak; Bcl2:Bak + In Progress MV4-11 IC50=123 nM In progress Mcl1:Bak In progress +

scholarly journals Ovarian Cancer HO-8910 Cell Apoptosis Induced by Crocin in vitro

2015 ◽  
Vol 10 (2) ◽  
pp. 1934578X1501000 ◽  
Author(s):  
Dan Xia
Keyword(s):  
Ovarian Cancer ◽  
Flow Cytometry ◽  
Western Blot ◽  
Blot Analysis ◽  
Cell Apoptosis ◽  
Western Blot Analysis ◽  
Caspase 3 ◽  
Cell Cycle Distribution ◽  
Apoptotic Pathway ◽  
Apoptosis Rate

The effect and mechanism of ovarian cancer HO-8910 cell apoptosis induced by crocin. MTT assay was performed to detect the inhibitory action of crocin on the proliferation of HO-8910 cells. Flow cytometry was used to test the cell cycle distribution and apoptosis rate of ovarian cancer HO-8910 cells. Western blot analysis was utilized to measure the levels of apoptotic proteins such as p53, Fas/APO-1, and Caspase-3. MTT analysis revealed that crocin significantly inhibited the growth of HO-8910 cells. Additionally, flow cytometry illustrated that crocin raised the proportion of HO-8910 cells in the G0/G1 phase and increased their apoptosis rate. Furthermore, Western blot analysis revealed that crocin up-regulated the expression of p53, Fas/APO-1, and Caspase-3. The results of this study showed that crocin can significantly inhibit the growth of HO-8910 cells and arrest them in the G0/G1 phase. Crocin can also promote ovarian cancer HO-8910 cell apoptosis, most likely by increasing p53 and Fas/APO-1 expression, and then activating the apoptotic pathway regulated by Caspase-3.

Effects of riluzole (RZ) and ionizing radiation (IR) in metabotropic glutamate receptor-1 (GRM1) positive human melanoma

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. 9083-9083
Author(s):  
C. Green ◽  
D. Schiff ◽  
A. Khan ◽  
S. Goyal ◽  
J. Goydos ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Flow Cytometry ◽  
Western Blot ◽  
Cell Survival ◽  
Glutamate Receptor ◽  
Blot Analysis ◽  
Caspase 3 ◽  
Metabotropic Glutamate Receptor ◽  
Human Melanoma ◽  
Metabotropic Glutamate

9083 Background: Melanoma has long been known to be relatively radio-resistant. GRM1 is a metabotropic glutamate receptor that has been detected in human melanoma cell lines and biopsies. Riluzole (RZ), a glutamate release inhibitor, has been shown to arrest GRM1 positive human melanoma cells in G2/M and sub-G1 phases of the cell cycle. The purpose of this study was to determine if RZ enhances the lethal effects of IR in human melanoma. Methods: ATP luminescence assays were performed. Clonogenic assays were performed and cell survival curves generated. Cell cycle analysis was performed utilizing flow cytometry. Western blot analysis was performed utilizing cleaved PARP and caspase-3 antibodies as markers of apoptosis. Results: Luminescence assays revealed 25uM Riluzole to be the necessary concentration for clonogenic assays. At 2Gy, there was a 48% reduction (p≤0.05) in cell survival in RZ-treated cells. At 4 Gy, there was a 19% reduction (p≤0.05) in cell survival in RZ-treated cells. No differences were seen at 6 and 8 Gy. Cell cycle analysis showed that the combination of IR and RZ was superior to IR alone in increasing the number of cells in sub-G1, which represents apoptotic death. Western blot analysis showed that the combination of IR and RZ showed yielded increased cleaved PARP and caspase-3 activity when compared to IR alone. Conclusions: Riluzole is a FDA approved drug that has long been used in ALS. It is relatively non-toxic and crosses the blood brain barrier. Our data shows that Riluzole in combination with radiation eliminates the radio-resistant shoulder of the C8161 survival curve. RZ and IR, as combination therapy are more lethal than IR or RZ alone in human melanoma, as demonstrated by flow cytometry and WB analysis. This data has promising implications for melanoma patients with brain metastases. No significant financial relationships to disclose.

Abstract 1958: MicroRNA Mir-27b Rescues Impaired Angiogenic Function of Endothelial Progenitor Cells and Accelerates Wound Healing in Type 2 Diabetes

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Jie-Mei Wang ◽  
Jun Tao ◽  
Alex F Chen
Keyword(s):  
Type 2 Diabetes ◽  
Wound Healing ◽  
Western Blot ◽  
Real Time ◽  
Blot Analysis ◽  
Real Time Pcr ◽  
Western Blot Analysis ◽  
Type 2 Diabetic

Endothelial progenitor cells (EPCs) play a key role in angiogenesis, which is dysfunctional in diabetes. MicroRNAs (miRNAs) are endogenous non-coding RNAs that regulate gene expression at the post-transcriptional level. However, whether miRNAs regulate EPC-mediated angiogenesis in diabetes is unknown. We tested the hypothesis that mir-27b rescues impaired EPC angiogenesis in vitro and in vivo via suppressing anti-angiogenic molecule thrombospondin-1 (TSP-1) in type 2 diabetes. Bone marrow-derived EPCs from adult male (C57BLKS/J, 9 weeks) type 2 diabetic db/db and their normal littermates db/+ mice (glucose 371.8±37.8 vs. 167.5±21.3 mg/dL, n=38, p<0.05) were used. miRNA processing enzyme Dicer in EPCs was decreased by >40% in db/db vs. db/+ mice (Western blot analysis, n=4 p<0.01), paralleled with >66% reduction of mir-27b expression (real-time PCR, n=4, p<0.05). Both TSP-1 mRNA and protein in EPCs were significantly higher in db/db vs. db/+ mice (real-time PCR, 130.1%, n=4, p<0.05, Western blot analysis, 127.4%, n=4 p<0.05), which were suppressed upon mir-27b mimic transfection (by 75%, real-time PCR and 69%, Western blot analysis, n=4 – 6, p<0.01). EPC-induced angiogenesis was decreased by >70% in db/db vs. db/+ mice (Matrigel tube formation assay, n=4, p<0.05), which was rescued upon mir-27b mimic transfection or silencing TSP-1 expression by its siRNA (both n=4, p<0.05). Furthermore, inhibition of mir-27b in normal EPCs increased their TSP-1 protein by 117.5% (n=6, p<0.05) and impaired their angiogenesis by 81.5% (n=4, p<0.01), both were reversed by silencing TSP-1 expression by its siRNA. Finally, excisional wound closure was markedly delayed in db/db vs. db/+ mice (4-mm punch biopsy, n=4, p<0.05), accompanied by impaired wound angiogenesis (perfusion index by Laser Doppler, n=4, p<0.05). Cell therapy of diabetic EPCs (3×10 5 cells) transfected with mir-27b mimic onto diabetic wounds significantly accelerated their closure rates (n=4, p<0.05 vs. diabetic EPCs alone), with a concomitant augmentation of in vivo wound angiogenesis (n=4, p<0.05). Mir-27b rescues impaired EPC angiogenesis and accelerates wound healing in type 2 diabetic mice, at least in part, via suppressing TSP-1 expression. This research has received full or partial funding support from the American Heart Association, AHA Midwest Affiliate (Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, South Dakota & Wisconsin).

Proteasome Inhibitors Can Induce Caspase-3 Activation and Apoptosis in Human CML Cell Lines.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4681-4681
Author(s):  
Byung-Su Kim ◽  
Chang Up Kim ◽  
Young-Ju Kim ◽  
Eun Kyung Bae ◽  
Jinhee Kim ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Western Blot ◽  
Cell Lines ◽  
Blot Analysis ◽  
Proteasome Inhibitor ◽  
Western Blot Analysis ◽  
Caspase 3 ◽  
Expression Patterns ◽  
Proteasome Inhibitors ◽  
Acridine Orange Staining

Abstract The proteasome is a multi-enzyme complex that provides the ubiquitin-dependent degradation of many cytoplasmic and nuclear proteins involved in cell cycle progression and apoptosis. Inhibition of the proteasome represents a promising approach for the treatment of cancer because it can lead to cell cycle arrest and activation of caspases in tumor cells. There are several proteasome inhibitors that have been reported to induce apoptosis in various tumors. However, the effect of proteasome inhibition in human myeloid leukemia has not been reported so far. In this study, we tested two peptide-aldehyde proteasome inhibitors (MG115, MG132) on two human CML cell lines (K562, KCL22). At first, we treated both cell lines for 24, 48 and 72 hours with different doses of MG115 and MG132 and cell viability was tested by MTT assay. It showed substantial time and dose dependent cytotoxicity in both CML cell lines. Acridine orange staining also revealed DNA fragmentation. We then performed caspase-3 colorimetric assay after treating both cell lines for 6, 12 and 24 hours with 0.78μM of MG115, MG132. K562 showed the continuous rising of caspase-3 activity, while KCL22 exhibited the initial increase and subsequent mild decrease of caspase-3 activity. In addition, western blot analysis showed the reduction of procaspase-3 expression. The expression of Bcl-2 and Bcl-XL was reduced by western blot. p21 expression was slightly increased and that of cyclin D1 was decreased. Additionally, the treatment of proteasome inhibitor in CML cell lines initially induced phosphorylation of Jun kinase. We next examined the expression of heat shock proteins (Hsp70, Hsp90) after treating for 6, 12, 24 hours with the same proteasome inhibitors. Western blot analysis results indicated that expression patterns were different between MG115 and MG132. MG115 induced the slight increase of Hsp70 and Hsp90 in K562, but the reduction of both in KCL22. Meanwhile, MG132 produced the decrease of Hsp70 and Hsp90 in both K562, KCL22. In summary, our work supports that a proteasome inhibitor can induce apoptosis in human CML cell lines. We are currently focusing on the combined effect of proteasome inhibitor and Hsp90 inhibitor on CML. IC50 of Proteasome Inhibitors Cell line Proteasome Inhibitor 24hr 48hr 72hr K562 MG115 3.01 μM 1.14 μM 0.59 μM K562 MG132 μ 2.13 M 1.03 μM 0.57 μM KCL22 MG115 156.92 μM 1.36 μM 0.73 μM KCL22 MG132 1.56 μM 0.93 μM μ 0.75 M

The Combination of a Histone Deacetylase (HDAC) Inhibitor with the BCL-2 Inhibitor GX15-070 Has Synergistic Antileukemia Effect by Inducing Both Apoptotic and Autophagic Pathways.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1633-1633
Author(s):  
Yue Wei ◽  
Tapan Kadia ◽  
Weigang Tong ◽  
Susan O’Brien ◽  
Jean Viallet ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Western Blot ◽  
Blot Analysis ◽  
Hdac Inhibitor ◽  
Caspase 3 ◽  
Single Agent ◽  
Apoptotic Cells ◽  
Caspase Activation ◽  
Apoptotic Protein ◽  
Induction Of Apoptosis

Abstract HDAC inhibitors have limited single agent clinical activity in leukemia, a probable effect of dysregulated proapoptotic pathways. We hypothesized that the combination of a HDAC inhibitor with a Bcl-2 inhibitor may result in synergistic antileukemia activity. To test this concept, we modeled in vitro the combination of MGCD0103, a class 1 specific HDAC inhibitor, with GX15-070 (Obatoclax), a novel Bcl-2 homology domain-3 (BH3) mimetic The cytotoxic potential of the combination was first assessed measuring cell viability using trypan blue extraction assays in leukemia cell lines HL60, U937, THP1, and Molt4. Mathematical modeling analysis indicated a strong synergistic effect of the combination of MGCD0103 and GX15-070 in terms of growth inhibition. Inhibitory effect of the combination at concentrations of MGCD0103 600 nM and GX15-070 200 nM was 64 fold the effect of single agent MGCD0103 and 16 fold that of GX15-070. Analysis of sequence of treatment indicated that the optimal sequence was addition of GX15-070 first followed by MGCD0103. We then analyzed the effect of the combination on the induction of apoptosis using Annexin V flow assays. The combination also showed a marked synergistic effect in terms of apoptosis induction (the combination was 217% more potent than single agent MGCD0103 and 79% more than GX15-070). Western blot analysis indicated that the use of the combination substantially enhanced the cleavage/activation of caspase-3 and the subsequent cleavage of caspase-3 substrate PARP. As demonstrated in AML and other cell types previously, we showed that GX15-070 dissociated the pro-apoptotic protein BAK from MCL-1. The release of BAK has been demonstrated to play an important role in caspase activation. Western blot analysis also demonstrated that while anti-apoptotic protein XIAP, the major inhibitor of caspase 3, was reduced in MGCD0103 treated cells, the reduction was enhanced with the combination. These results suggest that GX15-070 may sensitize XIAP to the down-regulation effect of MGCD0103, which in turn further activates caspase 3. The combinatory effect of BAK release by GX-15-070, with the suppression of XIAP by MGCD0103, that is potentiated by GX15-070, may play a critical role in the synergistic effect of these two agents on caspase activation, which then results in increased induction of apoptosis. Because in initial experiments we evidenced a discrepancy between cell viability and apoptosis, we also studied the effect of the combination on the induction of autophagy using electron microscopy: non-apoptotic cells after MGCD0103 treatment did not show increase autophagic characteristics compared to control cells, while more non-apoptotic cells under GX15-070 evidenced swollen endoreticulum, a feature of early autophagy. Most non-apoptotic cells treated with MGCD0103 and GX15-070 combination showed accumulation of macro-autophagosomes, a marker of late autophagy, indicating that more severe autophagy was induced by the combination. Furthermore, induction of LC3-II, a marker of autophagy, was observed after combination. We confirmed these results (both in terms of apoptosis and autophagy) ex vivo in primary cells (n=8) obtained from patients with relapsed/refractory AML. In conclusion, the combination of an HDAC inhibitor with GX15-070 has synergistic antileukemia activity and should be studied in human clinical trials.

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