Topotecan Induces -Apoptosis in the Myelodysplastic Syndromes Cell Line MUTZ-1 That Is Associated with down Regulation of IAP Expression.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4713-4713
Author(s):  
Zhen Cai ◽  
Wenjun Wu Master

Abstract Myelodysplastic syndromes (MDS) represent a heterogenous group of clonal stem cell disorders with qualitative and quantitative abnormalities of blood cells and a high probability of evolving to acute leukemia. Intensive induction chemotherapy in order to reduce the malignant clone and reconstruct normal hematopoiesis is a classic therapy of MDS, especially high risk MDS. Topotecan (TPT), a semisynthetic water-soluble derivative of camptothecin, is a potent inhibitor of DNA topoisomerase I and has been extensively studied in hematologic malignances. However, little is known about how TPT acts against neoplastic cells. The aim of this study is to evaluate apoptotic effect of TPT on the MDS cell line MUTZ-1 and its associated changes in the expression of inhibitors of apoptosis protein (IAPs). The effect of TPT on MUTZ-1 growth was determined by using MTT assay. Characteristics associated with apoptosis induced by TPT were evaluated by transmission electron microscope, DNA gel electrophoresis and flow cytometry (FCM). Cell cycle shift were observed by FCM. Semi-quantitative RT-PCR was used to evaluate the mRNA expression of members of IAP gene family, including survivin, XIAP, Bcl-2, Bax, cIAP1 andcIAP2. The potential of mitochondrial membrane potential (MMP) was determined by using JC-1 probe. The results demonstrated that TPT significantly inhibited MUTZ-1 cell growth in a time- and dose-dependent manner with IC50 of 5.011 mmol/L, 1.297mmol/L and 0.483mmol/L at 24h, 48h and 72h respectively. Morphological features associated with TPT-induced apoptosis observed by transmission electron microscopy included cytoplasmic and nuclear shrinkage, karyorrhexis, nuclear convolution, chromatin condensation and margination, cytoplasmic vacuolization, and membrane-bound apoptotic bodies. An ambiguous DNA ladder was observed following treatment with 5mmol/L TPT for 24h, and a typical DNA ladder was observed with 10mmol/L TPT for 24h. The apoptotic rates were 11.69±0.51%, 34.07±1.73%, and 48.59±2.01%, respectively, after 24h culture with TPT as 1, 5, 10 μmol/L, significantly higher than that of the control (3.47%±0.3%; F=31.642, P<0.01). The percentage of MUTZ-1 cells in G2/M phase of the cell cycle decreased while in S and G0/G1 phase increased after treatment with 1mmol/L TPT for 24h,. The majority of the cells were arrested in S phase. After 24h culture with TPT at1, 5, and 10μmol/L, the mRNA levels of survivin, XIAP, cIAP1 and cIAP2 were decreased (P<0.01). This down-regulation was negatively correlated with TPT-induced apoptotic rates(P<0.05). There was no significant change in the Bax and Bcl-2 mRNA levels after TPT treatment (P>0.05). After 24h culture with 1μmol/L TPT, the MMP of TPT treated cells decreased significantly(P<0.01). Together, we conclude TPT can inhibit the growth and induce apoptosis of MUTZ-1 cells in a time- and dose- dependent manner. TPT can also induce the cell cycle changes, with the majoritoy of cells being arrested in S phase. The TPT-induced apoptosis in MUTZ-1 cells is associated with down-regulation of suvivin, XIAP, cIAP1and cIAP2 mRNA expresison. As well, MMP may be play a important role in the apoptotic process of MUTZ-1 cells induced by TPT.

Reproduction ◽  
2015 ◽  
Vol 149 (2) ◽  
pp. 163-170 ◽  
Author(s):  
Meng-Ling Liu ◽  
Jing-Lei Wang ◽  
Jie Wei ◽  
Lin-Lin Xu ◽  
Mei Yu ◽  
...  

Tri-ortho-cresyl phosphate (TOCP) has been widely used as plasticizers, plastic softeners, and flame retardants in industry and reported to have a deleterious effect on the male reproductive system in animals besides delayed neurotoxicity. Our preliminary results found that TOCP could disrupt the seminiferous epithelium in the testis and inhibit spermatogenesis, but the precise mechanism is yet to be elucidated. This study shows that TOCP inhibited viability of rat spermatogonial stem cells in a dose-dependent manner. TOCP could not lead to cell cycle arrest in the cells; the mRNA levels of p21, p27, p53, and cyclin D1 in the cells were also not affected by TOCP. Meanwhile, TOCP did not induce apoptosis of rat spermatogonial stem cells. After treatment with TOCP, however, both LC3-II and the ratio of LC3-II/LC3-I were markedly increased; autophagy proteins ATG5 and beclin 1 were also increased after treatment with TOCP, indicating that TOCP could induce autophagy in the cells. Ultrastructural observation under the transmission electron microscopy indicated that autophagic vesicles in the cytoplasm containing extensively degraded organelles such as mitochondria and endoplasmic reticulum increased significantly after the cells were treated with TOCP. In summary, we have shown that TOCP can inhibit viability of rat spermatogonial stem cells and induce autophagy of the cells, without affecting cell cycle and apoptosis.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4616-4616
Author(s):  
Azhar R. Hussain ◽  
Naif A. Al-Jomah ◽  
Mehar Sultana ◽  
Manugaran S. Pulicat ◽  
Khawla S. Al-Kuraya ◽  
...  

Abstract Proteosome inhibition is a novel approach for treating malignancy and has been approved for clinical use. The proteosome is the primary proteolytic mechanism in eukaryotic cells and inhibition of its catalytic activity initiates a cascade of events affecting cell cycle and apoptotic activities. These activities ultimately lead to cell cycle arrest and apoptosis in malignant cells however, the normal counterpart of these cells are spared. In this study, we used a panel of primary effusion lymphoma cell lines (BC1, BC3, BCBL1 and HBL6) to study the effects of proteosome inhibitor, MG132 on cell proliferation and apoptosis. Our data showed that proteosome inhibitor MG132 decreased cell viability as well as induced apoptosis in a dose dependent manner ranging from 0.5–10μM. Furthermore, treatment with 2.5μM MG132 for 24hours induced 41% apoptosis in BC1, 51% in BC3, 41% in BCBL1 and 48% in HBL6 cell lines as detected by annexinV/PI dual staining. S-phase kinase-associated protein 2 (skp-2) is a proto-oncogene and over expressed in various types of tumors. We sought to determine the role of Skp-2 following proteosome inhibition in PELs. MG132 treatment of PEL cell lines resulted in down-regulation of SKP-2 protein in a dose dependent manner whereas the expression of p-27 was up-regulated demonstrating an inverse relationship between these two proteins. Furthermore, MG132 treatment of PELs led to conformational changes in Bax protein and translocation to the mitochondria leading to the loss of mitochondrial membrane potential with subsequent release of cytochrome c from mitochondria into cytosol. Cytochrome c release caused activation of caspase-3 followed by polyadenosin-5′-diphosphate-ribose polymerase (PARP) cleavage. In addition, proteosome inhibitor treatment also caused down-regulation of inhibitor of apoptosis protein, XIAP. Taken together, our findings show that proteosome inhibition causes down-regulation of skp-2, up-regulation of p-27, inhibition of proliferation as well as caspase-dependent apoptosis in primary effusion lymphoma cells suggesting a role of proteosome inhibitors in the treatment of these aggressive cancers.


2011 ◽  
Vol 39 (06) ◽  
pp. 1253-1260 ◽  
Author(s):  
Sang Mi Han ◽  
Joo Hong Yeo ◽  
Yoon Hee Cho ◽  
Sok Cheon Pak

For cosmetic reasons, the demand for effective and safe skin-whitening agents is high. Since the key enzyme in the melanin synthetic pathway is tyrosinase, many depigmenting agents in the treatment of hyperpigmentation act as tyrosinase inhibitors. In this study, we have investigated the hypo-pigmentary mechanism of royal jelly in a mouse melanocyte cell line, B16F1. Treatment of B16F1 cells with royal jelly markedly inhibited melanin biosynthesis in a dose-dependent manner. Decreased melanin content occurred through the decrease of tyrosinase activity. The mRNA levels of tyrosinase were also reduced by royal jelly. These results suggest that royal jelly reduces melanin synthesis by down-regulation of tyrosinase mRNA transcription and serves as a new candidate in the design of new skin-whitening or therapeutic agents.


Pharmacology ◽  
2019 ◽  
Vol 105 (3-4) ◽  
pp. 164-172
Author(s):  
Shuangbo Fan ◽  
Qian Xu ◽  
Liang Wang ◽  
Yulin Wan ◽  
Sheng Qiu

SMBA1 (small-molecule Bax agonists 1), a small molecular activator of Bax, is a potential anti-tumour agent. In the present study, we investigated the biological effects of SMBA1 on glioblastoma (GBM) cells. SMBA1 reduced the viabilities of U87MG, U251 and T98G cells in a time- and dose-dependent manner. Moreover, treatment with SMBA1 induced cell cycle arrest at the G2/M phase transition, accompanied by the downregulation of Cdc25c and cyclin B1 and the upregulation of p21. SMBA1 also induced apoptosis of GBM cells in a dose-dependent manner. Mechanistically, SMBA1 induced apoptosis via the intrinsic pathway. Silencing of Bax or ectopic expression of Bcl-2 significantly inhibited SMBA1-induced apoptosis. Moreover, SMBA1 inhibited the growth of U87MG xenograft tumours in vivo. Overall, SMBA1 shows anti-proliferative effects against GBM cells through activation of the intrinsic apoptosis pathway.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4246-4246
Author(s):  
Yusuf Baran ◽  
Emel Basak Gencer ◽  
Aylin Camgoz ◽  
Ferit Avcu ◽  
Ali Ugur Ural

Abstract Abstract 4246 Chronic myeloid leukemia (CML) is a hematological malignancy resulting from the reciprocal translocation of chromosomes 9 and 22 that generates BCR/ABL oncogene. Nilotinib is a rationally designed, specific BCR/ABL tyrosine kinase inhibitor. Ceramide is a novel regulator of cell growth and proliferation, differentiation, senescence, cell cycle and also acts a strong apoptotic molecule while its conversion to antiapoptotic glucosyle ceramide (GC) and sphingosine-1-phosphate (S1P) by glucosyle ceramide synthase (GCS) and sphingosine kinase-1 (SK-1) enzymes result in more aggressive and resistant cancers. In this study, we studied the roles of ceramide metabolising genes in nilotinib induced apoptosis and possibility of increasing the sensitivity of BCR/ABL positive K562 and Meg-01 cells to nilotinib through targeting ceramide metabolism. The cytotoxicity analyses of nilotinib, C8:ceramide to induce de novo generation of ceramides, 1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP) to inhibit GCS and SK1 inhibitor were conducted by XTT cell proliferation assay. The changes in caspase-3 enzyme activity and mitochondrial membrane potential (MMP) were measured by caspase-3 colorimetric assay and JC-1 MMP detection kit, respectively. Expression analyses of ceramide synthase (LASS) genes, SK-1 and GCS genes were performed by RT-PCR. We have shown that nilotinib induces apoptosis and inhibits cell-cycle progression in K562 and Meg-01 cells in a dose dependent manner. We have shown significant synergistic apoptotic effects of nilotinib in combination with C8:ceramide or PDMP or SK-1 inhibitor by XTT cell proliferation assay in addition to the changes in caspase-3 enzyme activity and changes in mitochondrial membrane potential, as compared to any agent alone. These results revealed that increasing de novo generation of ceramides or inhibiting conversion of ceramides to antiapoptotic GC or S1P increased sensitivity of BCR/ABL CML cells to nilotinib. More importantly, RT-PCR results revealed that there were significant decreases in expression levels of SK1 in response to increasing concentrations of nilotinib. On the other hand increases in expression levels of LASS2, -4, -5, and -6 ceramide synthase genes were determined in a dose dependent manner as compared to untreated controls. It was shown for the first time by this study that targeting ceramide metabolism in addition to inhibition of BCR/ABL by nilotinib induces apoptosis synergistically in BCR/ABL positive K562 and Meg-01 CML cells. This study was supported by The Scientific and Technological Council of Turkey Disclosures: No relevant conflicts of interest to declare.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Yong-Ge Guan ◽  
Jin-Bin Liao ◽  
Kun-Yin Li ◽  
Yu-Cui Li ◽  
Yang Song ◽  
...  

Background. Shaoyao-Gancao Decoction (SGD), a well-known traditional Chinese medicine prescription, has been widely used to treat adenomyosis, dysmenorrhea, abdominal pain, and inflammation in Asia. However, the mechanism underlying the effectiveness of SGD in the treatment of adenomyosis still remains elusive. The present study aimed to investigate the bioactivity of SGD and its underlying molecular mechanisms using cultured human adenomyosis-derived cells.Methods. Human adenomyosis-derived cells were treated with SGD and its major constituents (paeoniflorin and liquiritin)in vitro. Effects of SGD, paeoniflorin, and liquiritin on cell proliferation and apoptosis were examined by MTT assay and flow cytometry analyses. The effects of SGD, paeoniflorin, and liquiritin on the production of PGE2and PGF2αwere assayed using ELISA. ER-αand OTR mRNA expression levels were also evaluated by real-time qRT-PCR.Results. SGD, paeoniflorin, and liquiritin inhibited proliferation and induced apoptosis of human adenomyosis-derived cells in a dose-dependent manner. SGD and paeoniflorin significantly reduced the PGE2and PGF2αproduction. Furthermore, they remarkably decreased the mRNA levels of ER-αand OTR.Conclusions. The results of this study provide possible mechanisms for the bioactivity of SGD for treating adenomyosis and contribute to the ethnopharmacological knowledge about this prescription.


2021 ◽  
Author(s):  
Lamuk Zaveri ◽  
Jyotsna Dhawan

AbstractDuring reprogramming of somatic cells, heightened proliferation is one of the earliest changes observed. While other early events such as mesenchymal-to-epithelial transition have been well studied, the mechanisms by which the cell cycle switches from a slow cycling state to a faster cycling state are still incompletely understood. To investigate the role of Oct-3/4 in this early feature of reprogramming, we created a 4-Hydroxytamoxifen dependent Oct-3/4 Estrogen Receptor fusion (OctER). We show that OctER can substitute for Oct-3/4 to reprogram mouse embryonic fibroblasts to induced pluripotent stem cells. While over-expression of OctER or Klf4 individually did not affect cell proliferation, in combination, these factors hasten the cell cycle, in a tamoxifen dose-dependent manner, supporting a key role for OctER. Oct-3/4 + Klf4 increased proliferation by enhancing expression of Cyclin A2. We verified occupancy of endogenous Oct-3/4 and Klf4 at bioinformatically identified binding sites in the Cyclin A2 promoter in mouse embryonic stem cells (mESC). Using inducible OctER along with Klf4, we show dose-dependent induction of Cyclin A2 promoter-reporter activity and mRNA levels. Taken together, our results provide further evidence of the interdependence of pluripotency and the rapid cell cycle seen in mESC, and identify CyclinA2 as a key early target.


1999 ◽  
Vol 73 (4) ◽  
pp. 3154-3161 ◽  
Author(s):  
Matthew G. Davenport ◽  
Joseph S. Pagano

ABSTRACT Expression of EBNA-1 protein is required for the establishment and maintenance of the Epstein-Barr virus (EBV) genome during latent infection. During type I latency, the BamHI Q promoter (Qp) gives rise to EBNA-1 expression. The dominant regulatory mechanism for Qp appears to be mediated through the Q locus, located immediately downstream of the transcription start site. Binding of EBNA-1 to the Q locus represses Qp constitutive activity, and repression has been reported to be overcome by an E2F family member that binds to the Q locus and displaces EBNA-1 (N. S. Sung, J. Wilson, M. Davenport, N. D. Sista, and J. S. Pagano, Mol. Cell. Biol. 14:7144–7152, 1994). These data suggest that the final outcome of Qp activity is reciprocally controlled by EBNA-1 and E2F. Since E2F activity is cell cycle regulated, Qp activity and EBNA-1 expression are predicted to be regulated in a cell cycle-dependent manner. Proliferation of the type I latently infected cell line, Akata, was synchronized with the use of the G2/M blocking agent nocodazole. From 65 to 75% of cells could be made to peak in S phase without evidence of viral reactivation. Following release from G2/M block, EBNA-1 mRNA levels declined as the synchronized cells entered the G1 phase of the cell cycle. As cells proceeded into S phase, EBNA-1 mRNA levels increased parallel to the peak in cell numbers in S phase. However, EBNA-1 protein levels showed no detectable change during the cell cycle, most likely due to the protein’s long half-life as estimated by inhibition of protein synthesis by cycloheximide. Finally, in Qp luciferase reporter assays, the activity of Qp was shown to be regulated by cell cycle and to be dependent on the E2F sites within the Q locus. These findings demonstrate that transcriptional activity of Qp is cell cycle regulated and indicated that E2F serves as the stimulus for this regulation.


Viruses ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 196 ◽  
Author(s):  
Chuankuo Zhao ◽  
Mingshu Wang ◽  
Anchun Cheng ◽  
Qiao Yang ◽  
Ying Wu ◽  
...  

Background: Duck plague virus (DPV) can induce apoptosis in duck embryo fibroblasts (DEFs) and in infected ducks, but the molecular mechanism of DPV-induced apoptosis remains unknown. Methods: We first used qRT-PCR and a Caspase-Glo assay to determine whether the caspase protein family plays an important role in DPV-induced apoptosis. Then, we used an intracellular ROS detection kit and the mitochondrial probe JC-1 to respectively detect ROS levels and mitochondrial membrane potential (MMP). Finally, flow cytometry was used to detect apoptosis and cell cycle progression. Results: In this study, the mRNA levels and enzymatic activities of caspase-3, caspase-7, caspase-8, and caspase-9 were significantly increased during DPV-induced apoptosis. The caspase inhibitors Z-DEVD-FMK, Z-LEHD-FMK, and Q-VD-OphA could inhibit DPV-induced apoptosis and promote viral replication. Subsequently, a significant decrease in MMP and an increase in the intracellular ROS levels were observed. Further study showed that pretreating infected cells with NAC (a ROS scavenger) decreased the intracellular ROS levels, increased the MMP, inhibited apoptosis, and promoted viral replication. Finally, we showed that DPV infection can cause cell cycle S-phase arrest. Conclusions: This study shows that DPV causes cell cycle S-phase arrest and leads to apoptosis through caspase activation and increased intracellular ROS levels. These findings may be useful for gaining an understanding of the pathogenesis of DPV and the apoptotic pathways induced by α-herpesviruses.


Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5476
Author(s):  
Natsima Viriyaadhammaa ◽  
Aroonchai Saiai ◽  
Waranya Neimkhum ◽  
Wariya Nirachonkul ◽  
Wantida Chaiyana ◽  
...  

Curcuma comosa belongs to the Zingiberaceae family. In this study, two natural compounds were isolated from C. comosa, and their structures were determined using nuclear magnetic resonance. The isolated compounds were identified as 7-(3,4-dihydroxyphenyl)-5-hydroxy-1-phenyl-(1E)-1-heptene (1) and trans-1,7-diphenyl-5-hydroxy-1-heptene (2). Compound 1 showed the strongest cytotoxicity effect against HL-60 cells, while its antioxidant and anti-inflammatory properties were stronger than those of compound 2. Compound 1 proved to be a potent antioxidant, compared to ascorbic acid. Neither compounds had any effect on red blood cell haemolysis. Furthermore, compound 1 significantly decreased Wilms’ tumour 1 protein expression and cell proliferation in KG-1a cells. Compound 1 decreased the WT1 protein levels in a time- and dose- dependent manner. Compound 1 suppressed cell cycle at the S phase. In conclusion, compound 1 has a promising chemotherapeutic potential against leukaemia.


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