Antibiotic anisomycin induces cell cycle arrest and apoptosis through inhibiting mitochondrial biogenesis in osteosarcoma

The anti-cancer activities of antibiotic anisomycin have been demonstrated in kidney, colon and ovarian cancers whereas its underlying mechanisms are not well elucidated. In this work, we investigated whether anisomycin is effective in sensitizes osteosarcoma cell response to chemotherapy. We show that anisomycin inhibits proliferation via inducing osteosarcoma cell arrest at G2/M phase, accompanied by the increased levels of mitotic marker cyclin B and the decreased levels of Rb and E2F-1. Anisomycin also induces apoptosis in a caspase-dependent manner in osteosarcoma cells. Importantly, anisomycin is less effective in normal control NIH3T3 cells compared to osteosarcoma cells. In addition, anisomycin inhibits osteosarcoma growth in xenograft mouse model and enhances the inhibitory effects of doxorubicin in osteosarcoma in vitro and in vivo. Mechanistically, anisomycin targets mitochondrial biogenesis in osteosarcoma as shown by the decreased mitochondrial membrane potential, suppressed mitochondrial respiration via decreasing complex I activity, reduced ATP production. Furthermore, mitochondrial biogenesis stimulator acetyl-L-Carnitine (ALCAR) significantly rescues the inhibitory effects of anisomycin in osteosarcoma cells. Our work demonstrates that anisomycin is active against osteosarcoma cells and the molecular mechanism of its action is the inhibition of mitochondrial biogenesis.     

曲古霉素A诱导人膀胱癌细胞周期阻滞和凋亡的研究

目的:探讨组蛋白去乙酰化酶抑制剂曲古霉素A(TSA)对人膀胱癌T24细胞周期和凋亡的影响。方法:以不同剂量TSA(0.1μM,0.3μM和1μM)处理T24细胞。采用MTT法检测细胞存活率,AnnexinV-PI染色检测细胞凋亡,流式细胞仪检测caspase-3活性,Western blot法检测P21蛋白表达。结果:TSA剂量依赖性降低膀胱癌细胞存活率,促进细胞凋亡,表现为AnnexinV阳性细胞明显增多,同时活化的caspase-3水平增高。TSA还可通过诱导膀胱癌细胞周期阻滞于G2/M期抑制细胞生长,且呈剂量依赖性。结论:TSA通过促进caspase-3激活诱导膀胱癌细胞凋亡,同时诱导细胞阻滞于G2/M期。     

beta-lapachone induces cell cycle arrest and apoptosis in human colon cancer cells

BACKGROUND: Human colon cancers have a high frequency of p53 mutations, and cancer cells expressing mutant p53 tend to be resistant to current chemo- and radiation therapy. It is thus important to find therapeutic agents that can inhibit colon cancer cells with altered p53 status. beta-Lapachone, a novel topoisomerase inhibitor, has been shown to induce cell death in human promyelocytic leukemia and prostate cancer cells through a p53-independent pathway. Here we examined the effects of beta-lapachone on human colon cancer cells. MATERIALS AND METHODS: Several human colon cancer cell lines, SW480, SW620, and DLD1, with mutant or defective p53, were used. The antiproliferative effects of beta-lapachone were assessed by colony formation assays, cell cycle analysis, and apoptosis analysis, including annexin V staining and DNA laddering analysis. The effects on cell cycle and apoptosis regulatory proteins were examined by immunoblotting. RESULTS: All three cell lines, SW480, SW620, and DLD1, were sensitive to beta-lapachone, with an IC(50) of 2 to 3 microM in colony formation assays, a finding similar to that previously reported for prostate cancer cells. However, these cells were arrested in different stages of S phase. At 24 hr post-treatment, beta-lapachone induced S-, late S/G2-, and early S-phase arrest in SW480, SW620, and DLD1 cells, respectively. The cell cycle alterations induced by beta-lapachone were congruous with changes in cell cycle regulatory proteins such as cyclin A, cyclin B1, cdc2, and cyclin D1. Moreover, beta-lapachone induced apoptosis, as demonstrated by annexin V staining, flow cytometric analysis of DNA content, and DNA laddering analysis. Furthermore, down-regulation of mutant p53 and induction of p27 in SW480 cells, and induction of pro-apoptotic protein Bax in DLD1 cells may be pertinent to the anti-proliferative and apoptotic effects of beta-lapachone on these cells. CONCLUSIONS: beta-Lapachone induced cell cycle arrest and apoptosis in human colon cancer cells through a p53-independent pathway. For human colon cancers, which often contain p53 mutations, beta-lapachone may prove to be a promising anticancer agent that can target cancer cells, especially those with mutant p53.     

Pycnidione, a fungus-derived agent, induces cell cycle arrest and apoptosis in A549 human lung cancer cells

Pycnidione, a small tropolone first isolated from the fermented broth of Theissenia rogersii 92031201, exhibits antitumor activities through an undefined mechanism. The present study evaluated the effects and mechanisms of pycnidione on the growth and death of A549 human lung cancer cells. Pycnidione significantly inhibited the proliferation of A549 cells in a concentration-dependent manner, with a 50% growth inhibition (GI(50)) value of approximately 9.3nM at 48h. Pycnidione significantly decreased the expression of cyclins D1 and E and induced G(1)-phase cell cycle arrest and a subsequent increase in the sub-G(1) phase population. Pycnidione also markedly reduced the expression of survivin and activated caspase-8 and -3, increased reactive oxygen species (ROS) generation, caused the collapse of the mitochondrial membrane potential (MMP), and enhanced PAI-1 production, thus triggering apoptosis in the A549 cells. Taken together, pycnidione exerts anti-proliferative effects on human lung cancer cells through the induction of cell cycle arrest and apoptosis. Therefore, testing of its effects in vivo is warranted to evaluate its potential as a therapeutic agent against lung cancer.     

FTY720 induces cell cycle arrest and apoptosis of rat glomerular mesangial cells

The present study aimed to examine the effect of FTY720, a new immunosuppressive agent, on the proliferation and apoptosis of glomerular mesangial cells (GMC), and investigate the underlying mechanisms. Cultured rat GMC were treated by FTY720, and the cell viability, apoptosis and cell cycle progression were examined. Furthermore, cell cycle related gene expression profile was analyzed by cDNA microarray, and the protein expression of cell cycle related genes as well as Bax and Bcl-2 were examined by Western blot. The results showed that FTY720 inhibited GMC proliferation and induced apoptosis of GMC in a dose- and time-dependent manner, and induced G(1) phase cell cycle arrest in GMC in a dose-dependent manner as well. cDNA microarray analysis revealed that FTY720 regulated the expression of cell cycle-related gene. Western blot analysis showed that FTY720 induced the downregulation of cyclin D1, cyclin E, CDK2, CDK4, Bcl-2 and E2F1 and the upregulation of Kip1/p27, Cip1/p21, Bax and Rb in GMC in a dose-dependent manner. These results demonstrated that FTY720 could inhibit the proliferation of GMC through inducing cell cycle arrest and apoptosis, probably via the regulation of the expression of cell cycle-related genes and Bax/Bcl-2.     

Acetonic extract of Buxus sempervirens induces cell cycle arrest, apoptosis and autophagy in breast cancer cells

Plants are an invaluable source of potential new anti-cancer drugs. Here, we investigated the cytotoxic activity of the acetonic extract of Buxus sempervirens on five breast cancer cell lines, MCF7, MCF10CA1a and T47D, three aggressive triple positive breast cancer cell lines, and BT-20 and MDA-MB-435, which are triple negative breast cancer cell lines. As a control, MCF10A, a spontaneously immortalized but non-tumoral cell line has been used. The acetonic extract of Buxus sempervirens showed cytotoxic activity towards all the five studied breast cancer cell lines with an IC(50) ranging from 7.74 μg/ml to 12.5 μg/ml. Most importantly, the plant extract was less toxic towards MCF10A with an IC(50) of 19.24 μg/ml. Fluorescence-activated cell sorting (FACS) analysis showed that the plant extract induced cell death and cell cycle arrest in G0/G1 phase in MCF7, T47D, MCF10CA1a and BT-20 cell lines, concomitant to cyclin D1 downregulation. Application of MCF7 and MCF10CA1a respective IC(50) did not show such effects on the control cell line MCF10A. Propidium iodide/Annexin V double staining revealed a pre-apoptotic cell population with extract-treated MCF10CA1a, T47D and BT-20 cells. Transmission electron microscopy analyses indicated the occurrence of autophagy in MCF7 and MCF10CA1a cell lines. Immunofluorescence and Western blot assays confirmed the processing of microtubule-associated protein LC3 in the treated cancer cells. Moreover, we have demonstrated the upregulation of Beclin-1 in these cell lines and downregulation of Survivin and p21. Also, Caspase-3 detection in treated BT-20 and T47D confirmed the occurrence of apoptosis in these cells. Our findings indicate that Buxus sempervirens extract exhibit promising anti-cancer activity by triggering both autophagic cell death and apoptosis, suggesting that this plant may contain potential anti-cancer agents for single or combinatory cancer therapy against breast cancer.     

MK-2206 induces cell cycle arrest and apoptosis in HepG2 cells and sensitizes TRAIL-mediated cell death

It has become evident that AKT inhibitors have great potential in cancer treatment. In this study, we investigate the anticancer activity of MK-2206, a novel AKT inhibitor, on HepG2 hepatocellular carcinoma cell, and to show whether MK-2206 enhances the apoptosis-inducing potential of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). The cell growth inhibition was evaluated by MTT assay and colony formation assay. Cell cycle distribution was assessed by propidium iodide flow cytometry. Apoptosis was determined by AnnexinV-FITC/PI double staining assay and caspase-9, casapse-7, caspase-3, and PARP cleavage. The results of present study showed that MK-2206-induced G1-phase arrest was associated with a marked decrease in the protein expression of cyclin D1 with concomitant induction of p21 and p27. MK-2206-induced apoptosis was characterized by cleavage of a pro-caspase in a concentration-dependent manner. Moreover, the MAP family kinases p38 kinase and JNK were activated by exposure to MK-2206. SB203580, an p38-specific inhibitor, partially blocked MK-2206-induced death of HepG2 cells and caspase activation. A combination of MK-2206 with TRAIL significantly inhibited growth of TRAIL resistant HepG2 cells. Taken together, our findings provide a new insight to better understand anticancer mechanisms of MK-2206, at least in HepG2 cell. Using of MK-2206 as a potent sensitizer to TRAIL-induced apoptotic cell death offers a promising means of enhancing the efficacy of TRAIL-based HCC treatments.     

Dimethylfumarate induces cell cycle arrest and apoptosis via regulating intracellular redox systems in HeLa cells

Dimethylfumarate (DMF) is cytotoxic to several kinds of cells and serves as an anti-tumor drug. This study was designed to investigate the effects and underlying mechanism of DMF on cervical cancer cells. HeLa cells were cultured and treated with 0, 50, 100, 150, and 200 μM DMF, respectively. After 24 h, cell growth was evaluated using Cell Counting Kit-8 (CCK-8) assay and the cell cycle was examined using flow cytometry. In addition, cell apoptosis was detected by Annexin V/propidium iodide (PI) staining and the expressions of caspase-3 and poly-ADP-ribose polymerase (PARP) were detected using western blotting. The redox-related factors were then assessed. Furthermore, all of the indicators were detected in HeLa cells after combined treatment of DMF and N-acetyl-l-cysteine (NAC, an oxygen-free radical scavenger). The cell number and cell growth of HeLa were obviously inhibited by DMF in a dose-dependent manner, as the cell cycle was arrested at G0/G1 phase (P?<?0.05). The apoptotic HeLa cells were markedly increased, and the expression levels of caspase-3 and PARP were significantly increased in a DMF concentration-dependent way (P?<?0.05). Meanwhile, loss of △Ψm, increase in reactive oxygen species and O₂ ^·?, and the decrease in catalase activity and glutathione (GSH) level were found after DMF treatment (P?<?0.05). All these changes were significantly attenuated and even completely disappeared by adding NAC (P?<?0.05). In conclusion, the cytotoxicity of DMF on cell proliferation and apoptosis of HeLa cells was mainly related to the intracellular redox systems by depletion of intracellular GSH.     

Centaurea bruguierana inhibits cell proliferation,causes cell cycle arrest,and induces apoptosis in human MCF-7 breast carcinoma cells

Molecular Biology Reports - Centaurea bruguierana, of the Asteraceae family, has a long history of use in traditional medicines for the treatment of various ailments. However, the anticancer...     

Disruption of p97/VCP induces autophagosome accumulation,cell cycle arrest and apoptosis in human choriocarcinoma cells

Molecular Biology Reports - Gestational choriocarcinoma is aggressive trophoblastic disease. The development, progression and the cure of this disease is not well-established. p97/Valosin...     

Andrographolide induces cell cycle arrest and apoptosis in human rheumatoid arthritis fibroblast-like synoviocytes

The pseudo-tumoral expansion of fibroblast-like synoviocytes is a hallmark of rheumatoid arthritis (RA), and targeting rheumatoid arthritis fibroblast-like synoviocytes (RAFLSs) may have therapeutic potentials in this disease. Andrographolide, a diterpenoid compound isolated from the herb Andrographis paniculata, has been reported to have potent anti-inflammatory activity. In the present study, we aimed to investigate the effects of andrographolide on human RAFLSs and the underlying molecular mechanism(s). RAFLSs were isolated from patients with RA and treated with or without various concentrations (i.e., 10, 20, and 30 μM) of andrographolide for 48 h. 3-[4,5-Dimethyl-2-yl]-2,5-diphenyl tetrazolium bromide assay revealed that andrographolide treatment decreased the proliferation of RAFLSs in a dose-dependent manner. Cell cycle analysis using propidium iodide (PI) staining showed a G0/G1 cell cycle arrest in andrographolide-treated RAFLSs. Immunoblotting analysis of key cell cycle regulators demonstrated that andrographolide treatment caused a dose-dependent increase in the expression of cell-cycle inhibitors p21 and p27 and a concomitant reduction of cyclin-dependent kinase 4. Exposure to andrographolide-induced apoptosis of RAFLSs measured by annexin V/PI double staining, which was coupled with promotion of cytochrome C release from mitochondria and activation of caspase-3. Moreover, andrographolide-treated RAFLSs displayed a significant decrease in the Bcl-2/Bax ratio compared to untreated cells. In conclusion, our data demonstrate that andrographolide exerts anti-growth and pro-apoptotic effects on RAFLSs, thus may have therapeutic potential for the treatment of RA.     

Structure-function relationship for saponin effects on cell cycle arrest and apoptosis in the human 1547 osteosarcoma cells: a molecular modelling approach of natural molecules structurally close to diosgenin

In this paper, eight natural molecules structurally close to diosgenin (five saponins: diosgenin, hecogenin, tigogenin, sarsasapogenin, smilagenin; two steroidal alkaloids: solasodine, solanidine; one sterol: stigmasterol) have been tested for their biological activities on human 1547 osteosarcoma cells. Differences in activity were studied in term of proliferation rate, cell cycle distribution and apoptosis induction. By using molecular modelling, two structural characteristics were calculated: spatial conformation and electron transfer capacity. The second property has been investigated by the HOMO repartition and the corresponding energy. Correlation between the experimental and the theoretical data permit us to highlight the importance of the hetero-sugar moiety and the 5,6-double bond in the biological activity (apoptosis and cell cycle arrest) on the human 1547 cell line. The importance of conformation at C-5 and C-25 carbon atoms was also discussed.     

A resveratrol analog, phoyunbene B, induces G2/M cell cycle arrest and apoptosis in HepG2 liver cancer cells

Among the seven natural resveratrol analogs separated and identified from Pholidota yunnanensis R(OLFE), we found phoyunbene B (PYB, trans-3,4'-dihydroxy-2',3',5-trimethoxystilbene) was more effective in inhibiting the growth of HepG2 hepatocellular carcinoma cells than resveratrol. The inhibitory effect of PYB in HepG2 cells was due to its induction of G2/M cell cycle arrest and apoptosis. Induction of G2/M phase cell cycle arrest by PYB was associated with its up-regulation of Cyclin B1, while its induction of apoptosis was accompanied with its down-regulation of Bcl-2 and up-regulation of Bax. Our in vitro invasion/migration assays also showed that PYB could inhibit the invasion of hepatocellular carcinoma cells.     

Tocotrienol-rich fraction of palm oil induces cell cycle arrest and apoptosis selectively in human prostate cancer cells

One of the requisite of cancer chemopreventive agent is elimination of damaged or malignant cells through cell cycle inhibition or induction of apoptosis without affecting normal cells. In this study, employing normal human prostate epithelial cells (PrEC), virally transformed normal human prostate epithelial cells (PZ-HPV-7), and human prostate cancer cells (LNCaP, DU145, and PC-3), we evaluated the growth-inhibitory and apoptotic effects of tocotrienol-rich fraction (TRF) extracted from palm oil. TRF treatment to PrEC and PZ-HPV-7 resulted in almost identical growth-inhibitory responses of low magnitude. In sharp contrast, TRF treatment resulted in significant decreases in cell viability and colony formation in all three prostate cancer cell lines. The IC(50) values after 24h TRF treatment in LNCaP, PC-3, and DU145 cells were in the order 16.5, 17.5, and 22.0 microg/ml. TRF treatment resulted in significant apoptosis in all the cell lines as evident from (i) DNA fragmentation, (ii) fluorescence microscopy, and (iii) cell death detection ELISA, whereas the PrEC and PZ-HPV-7 cells did not undergo apoptosis, but showed modestly decreased cell viability only at a high dose of 80 microg/ml. In cell cycle analysis, TRF (10-40 microg/ml) resulted in a dose-dependent G0/G1 phase arrest and sub G1 accumulation in all three cancer cell lines but not in PZ-HPV-7 cells. These results suggest that the palm oil derivative TRF is capable of selectively inhibiting cellular proliferation and accelerating apoptotic events in prostate cancer cells. TRF offers significant promise as a chemopreventive and/or therapeutic agent against prostate cancer.     

A novel platinum compound inhibits constitutive Stat3 signaling and induces cell cycle arrest and apoptosis of malignant cells

Previous studies have established constitutive activation of Stat3 protein as one of the molecular changes required for tumorigenesis. To develop novel therapeutics for tumors harboring constitutively active Stat3, compounds from the NCI 2000 diversity set were evaluated for inhibition of Stat3 DNA-binding activity in vitro. Of these, a novel platinum (IV) compound, IS3 295, interacted with Stat3 and inhibited its binding to specific DNA-response elements. Further analysis suggested noncompetitive-type kinetics for the inhibition of Stat3 binding to DNA. In human and mouse tumor cell lines with constitutively active Stat3, IS3 295 selectively attenuated Stat3 signaling, thereby inducing cell growth arrest at G0/G1 phase and apoptosis. Moreover, in transformed cells, IS3 295 repressed expression of cyclin D1 and bcl-xL, two of the known Stat3-regulated genes that are overexpressed in malignant cells, suggesting that IS3 295 mediates anti-tumor cell activity in part by blocking Stat3-mediated sub-version of cell growth and apoptotic signals. Together, our findings provide evidence for the inhibition of Stat3 activity and biological functions by IS3 295 through interaction with Stat3 protein. This study represents a significant advance in small molecule-based approaches to target Stat3 and suggests potential new applications for platinum (IV) complexes as modulators of the Stat3 pathway for cancer therapy.     

Epidermal growth factor induces cell cycle arrest and apoptosis of squamous carcinoma cells through reduction of cell adhesion

Most squamous epithelial cells are strictly anchorage-dependent cell types. We observed that epidermal growth factor (EGF) promoted the growth of A431 squamous carcinoma cells in suspension cultures but suppressed cell growth and induced apoptosis in monolayer cultures, suggesting that loss of adhesion is responsible for the effects observed in monolayer culture, before cell death. Consistent with this finding, we demonstrated that EGF reduced cell attachment, cell-cell interaction, and cell spreading. Treatment with EGF increased cell adhesion-regulated expression of p21 but suppressed expressions of cyclin A, D1, cdk2, and retinoblastoma protein (pRb), leading to cell cycle arrest and adhesion-regulated programmed cell death. To test directly whether promoting cell adhesion could reduce the effects of EGF, we grew cultures on plates coated with type II collagen. On these plates, cell adhesion was enhanced and EGF treatment had little effect on cell adhesion and apoptosis when cells were attached to the collagen. The collagen effects were dose dependent, and cell cycle and cell cycle-associated proteins were altered accordingly. Finally, when cultures were plated on bacterial Petri dishes, which completely disrupted cell attachment to substratum, the level of apoptosis was greatly higher and cell cycle was arrested as compared with monolayer cultures. Taken together, our results strongly suggest that the EGF-induced cell cycle arrest and apoptosis in monolayer cultures was the result of a decline in cell adhesion.