Epstein-Barr virus (EBV) is a ubiquitous tumor-causing virus which infects more than 90% of the world population asymptomatically. Recent studies suggest that LMP-1, -2A and -2B cooperate in the tumorigenesis of EBV-associated epithelial cancers such as nasopharygeal carcinoma, oral and gastric cancer. In this study, LMPs were expressed in the HEK293T cell line to reveal their oncogenic mechanism via investigation on their involvement in the regulation of the cell cycle and genes that are involved. LMPs were expressed in HEK293T in single and co-expression manner. The transcription of cell cycle arrest genes were examined via real-time PCR. Cell cycle progression was examined via flow cytometry. 14-3-3σ and Reprimo were upregulated in all LMP-1 expressing cells. Moreover, cell cycle arrest at G(2)/M progression was detected in all LMP-1 expressing cells. Therefore, we conclude that LMP-1 may induce cell cycle arrest at G(2)/M progression via upregulation of 14-3-3σ and Reprimo.
Cell proliferation and cell death abnormalities are strongly linked to the development of cancer, including lung cancer. The purpose of this study was to investigate the effect of pterostilbene on cell proliferation and cell death via cell cycle arrest during the transition from G1 to S phase and the p53 pathway. A total of 24 female Balb/C mice were randomly categorized into four groups (n = 6): N-nitroso-tris-chloroethyl urea (NTCU) induced SCC of the lungs, vehicle control, low dose of 10 mg/kg PS + NTCU (PS10), and high dose of 50 mg/kg PS + NTCU (PS50). At week 26, all lungs were harvested for immunohistochemistry and Western blotting analysis. Ki-67 expression is significantly lower, while caspase-3 expression is significantly higher in PS10 and PS50 as compared to the NTCU (p cell cycle arrest.
Helicobacter pylori at multiplicity of infection (MOI ≥ 50) have been shown to cause apoptosis in RAW264.7 monocytic macrophage cells. Because chronic gastric infection by H. pylori results in the persistence of macrophages in the host's gut, it is likely that H. pylori is present at low to moderate, rather than high numbers in the infected host. At present, the effect of low-MOI H. pylori infection on macrophage has not been fully elucidated. In this study, we investigated the genome-wide transcriptional regulation of H. pylori-infected RAW264.7 cells at MOI 1, 5 and 10 in the absence of cellular apoptosis. Microarray data revealed up- and down-regulation of 1341 and 1591 genes, respectively. The expression of genes encoding for DNA replication and cell cycle-associated molecules, including Aurora-B kinase (AurkB) were down-regulated. Immunoblot analysis verified the decreased expression of AurkB and downstream phosphorylation of Cdk1 caused by H. pylori infection. Consistently, we observed that H. pylori infection inhibited cell proliferation and progression through the G1/S and G2/M checkpoints. In summary, we suggest that H. pylori disrupts expression of cell cycle-associated genes, thereby impeding proliferation of RAW264.7 cells, and such disruption may be an immunoevasive strategy utilized by H. pylori.
Imatinib mesylate is an anti‑neoplastic targeted chemotherapeutic agent, which can inhibit tyrosine kinase receptors, including BCR‑ABL, platelet‑derived growth factor receptors (PDGFRs) and c‑Kit. Cellular processes, including differentiation, proliferation and survival are regulated by these receptors. The present study aimed to evaluate the antiproliferative effects of imatinib mesylate, and its effects on apoptotic induction and cell cycle arrest in breast cancer cell lines. In addition, the study aimed to determine whether the effects of this drug were associated with the mRNA and protein expression levels of PDGFR‑β, c‑Kit, and their corresponding ligands PDGF‑BB and stem cell factor (SCF), which may potentially modulate cell survival and proliferation. To assess the antiproliferative effects of imatinib mesylate, an MTS assay was conducted following treatment of cells with 2‑10 µM imatinib mesylate for 96, 120 and 144 h; accordingly the half maximal inhibitory concentration of imatinib mesylate was calculated for each cell line. In addition, the proapoptotic effects and cytostatic activity of imatinib mesylate were investigated. To evaluate the expression of imatinib‑targeted genes, PDGFR‑β, c‑Kit, PDGF‑BB and SCF, under imatinib mesylate treatment, mRNA expression was detected using semi‑quantitative polymerase chain reaction and protein expression was detected by western blot analysis in ZR‑75‑1 and MDA‑MB‑231 breast carcinoma cell lines. Treatment with imatinib mesylate suppressed cell proliferation, which was accompanied by apoptotic induction and cell cycle arrest in the investigated cell lines. In addition, PDGFR‑β, PDGF‑BB, c‑Kit and SCF were expressed in both breast carcinoma cell lines; PDGFR‑β and c‑Kit, as imatinib targets, were downregulated in response to imatinib mesylate treatment. The present results revealed that at least two potential targets of imatinib mesylate were expressed in the two breast carcinoma cell lines studied. In conclusion, the antiproliferative, cytostatic and proapoptotic effects of imatinib mesylate may be the result of a reduction in the expression of c‑Kit and PDGFR tyrosine kinase receptors, thus resulting in suppression of the corresponding ligand PDGF‑BB. Therefore, imatinib mesylate may be considered a promising target therapy for the future treatment of breast cancer.
The current study investigated the anticancer properties of gold nanoparticles (SG-stabilized AuNPs) synthesized using water extracts of the brown seaweed Sargassum glaucescens (SG). SG-stabilized AuNPs were characterized by ultraviolet-visible spectroscopy, transmission and scanning electron microscopy, and energy dispersive X-ray fluorescence spectrometry. The SG-stabilized AuNPs were stable and small at 3.65 ± 1.69 nm in size. The in vitro anticancer effect of SG-stabilized AuNPs was determined on cervical (HeLa), liver (HepG2), breast (MDA-MB-231) and leukemia (CEM-ss) cell lines using fluorescence microscopy, flow cytometry, caspase activity determination, and MTT assays. After 72 h treatment, SG-stabilized AuNPs was shown to be significant (p < 0.05) cytotoxic to the cancer cells in a dose- and time-dependent manner. The IC50 values of SG-stabilized AuNPs on the HeLa, HepG2, CEM-ss, MDA-MB-231 cell lines were 4.75 ± 1.23, 7.14 ± 1.45, 10.32 ± 1.5, and 11.82 ± 0.9 μg/mL, respectively. On the other hand, SG-stabilized AuNPs showed no cytotoxic effect towards the normal human mammary epithelial cells (MCF-10A). SG-stabilized AuNPs significantly (p < 0.05) arrest HeLa cell cycle at G2/M phase and significantly (p < 0.05) activated caspases-3 and -9 activities. The anticancer effect of SG-stabilized AuNPs is via the intrinsic apoptotic pathway. The study showed that SG-stabilized AuNPs is a good candidate to be developed into a chemotherapeutic compound for the treatment of cancers especially cervical cancer.
The t(8;21) translocation is one of the most frequent chromosome abnormalities associated with acute myeloid leukaemia (AML). This abberation deregulates numerous molecular pathways including the ERK signalling pathway among others. Therefore, the aim of the present study was to investigate the gene expression patterns following siRNA‑mediated suppression of RUNX1‑RUNX1T1 and MAPK1 in Kasumi‑1 and SKNO‑1 cells and to determine the differentially expressed genes in enriched biological pathways. BeadChip microarray and gene ontology analysis revealed that RUNX1‑RUNX1T1 and MAPK1 suppression reduced the proliferation rate of the t(8;21) cells with deregulated expression of several classical positive regulator genes that are otherwise known to enhance cell proliferation. RUNX1‑RUNX1T1 suppression exerted an anti‑apoptotic effect through the overexpression of BCL2, BIRC3 and CFLAR genes, while MAPK1 suppression induced apopotosis in t(8;21) cells by the apoptotic mitochondrial changes stimulated by the activity of upregulated TP53 and TNFSF10, and downregulated JUN gene. RUNX1‑RUNX1T1 suppression supported myeloid differentiation by the differential expression of CEBPA, CEBPE, ID2, JMJD6, IKZF1, CBFB, KIT and CDK6, while MAPK1 depletion inhibited the differentiation of t(8;21) cells by elevated expression of ADA and downregulation of JUN. RUNX1‑RUNX1T1 and MAPK1 depletion induced cell cycle arrest at the G0/G1 phase. Accumulation of cells in the G1 phase was largely the result of downregulated expression of TBRG4, CCNE2, FOXO4, CDK6, ING4, IL8, MAD2L1 and CCNG2 in the case of RUNX1‑RUNX1T1 depletion and increased expression of RASSF1, FBXO6, DADD45A and P53 in the case of MAPK1 depletion. Taken together, the current results demonstrate that MAPK1 promotes myeloid cell proliferation and differentiation simultaneously by cell cycle progression while suppresing apoptosis.
Artonin E is a prenylated flavonoid isolated from the stem bark of Artocarpus elasticus Reinw.(Moraceae). This study aimed to investigate the apoptotic mechanisms induced by artonin E in a metastatic human ovarian cancer cell line SKOV-3 in vitro. MTT assay, clonogenic assay, acridine orange and propidium iodide double staining, cell cycle and annexin V analyses were performed to explore the mode of artonin E-induced cell death at different time points. DNA laddering, activation of caspases-3, -8, and -9, multi-parametric cytotoxicity-3 analysis by high-content screening, measurement of reactive oxygen species generation, and Western blot were employed to study the pathways involved in the apoptosis. MTT results showed that artonin E inhibited the growth of SKOV-3 cells, with IC50 values of 6.5±0.5 μg/mL after 72 h treatment, and showed less toxicity toward a normal human ovarian cell line T1074, with IC50 value of 32.5±0.5 μg/mL. Results showed that artonin E induced apoptosis and cell cycle arrest at the S phase. This compound also promoted the activation of caspases-3, -8, and -9. Further investigation into the depletion of mitochondrial membrane potential and release of cytochrome c revealed that artonin E treatment induced apoptosis via regulation of the expression of pro-survival and pro-apoptotic Bcl-2 family members. The expression levels of survivin and HSP70 proteins were also down regulated in SKOV-3 cells treated with artonin E. We propose that artonin E induced an antiproliferative effect that led to S phase cell cycle arrest and apoptosis through dysregulation of mitochondrial pathways, particularly the pro- and anti-apoptosis signaling pathways.
Matched MeSH terms: S Phase Cell Cycle Checkpoints/genetics