Imperatorin induces autophagy and G0/G1 phase arrest via PTEN-PI3K-AKT-mTOR/p21 signaling pathway in human osteosarcoma cells in vitro and in vivo
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ABSTRACT: Imperatorin induces autophagy and G0/G1 phase arrest via PTEN-PI3K-AKT-mTOR/p21 signaling pathway in human osteosarcoma cells in vitro and in vivo
Project description:Osteosarcoma is the third most common cancer in adolescence and the first common primary malignant tumor of bone. The long-term prognosis of osteosarcoma, especially for unresectable and metastatic tumors, still remains unsatisfactory in the past decades. In this study, we systematically investigated the antitumor effect of imperatorin (IMP), a small molecule extracted from Angelica dahurica, in human osteosarcoma cells. The results showed that IMP triggered time-dependent and dose-dependent inhibition of tumor growth mainly by inducing autophagy promotion and G0/G1 phase arrest in vitro and in vivo. Besides, IMP treatment elevated the expression level of PTEN and p21, down-regulated the phosphorylation of AKT and mTOR. In contrast, the inhibition of PTEN using Bpv (HOpic), a potential and selective inhibitor of PTEN, concurrently rescued IMP-induced autophagy promotion, cell cycle arrest and inactivation of PTEN-PI3K-AKT-mTOR/p21 pathway. Taken together, our data revealed that imperatorin induced autophagy and cell cycle arrest through PTEN-PI3K-AKT-mTOR/p21 signaling pathway by targeting and up-regulating PTEN in human osteosarcoma cells. Hence, imperatorin is a desirable candidate for clinical treatments of osteosarcoma.
Project description:BackgroundOsteosarcoma is the third most common cancer in adolescence and the first common primary malignant tumor of bone. The long-term prognosis of osteosarcoma still remains unsatisfactory in the past decades. Therefore, development of novel therapeutic agents which are effective to osteosarcoma and are safe to normal tissue simultaneously is quite essential and urgent.MethodsFirstly, MTT assay, cell colony formation assay, cell migration and invasion assays were conducted to evaluate the inhibitory effects of imperatorin towards human osteosarcoma cells. RNA-sequence assay and bioinformatic analysis were then performed to filtrate and assume the potential imperatorin-induced cell death route and signaling pathway. Moreover, quantitative real-time PCR assay, western blot assay and rescue experiments were conducted to confirm the assumptions of bioinformatic analysis. Finally, a subcutaneous tumor-transplanted nude mouse model was established and applied to evaluate the internal effect of imperatorin on osteosarcoma by HE and immunohistochemistry staining.ResultsImperatorin triggered time-dependent and dose-dependent inhibition of tumor growth mainly by inducing autophagy promotion and G0/G1 phase arrest in vitro and in vivo. Besides, imperatorin treatment elevated the expression level of PTEN and p21, down-regulated the phosphorylation of AKT and mTOR. In contrast, the inhibition of PTEN using Bpv (HOpic), a potential and selective inhibitor of PTEN, concurrently rescued imperatorin-induced autophagy promotion, cell cycle arrest and inactivation of PTEN-PI3K-AKT-mTOR/p21 pathway.ConclusionsThis work firstly revealed that imperatorin induced autophagy and cell cycle arrest through PTEN-PI3K-AKT-mTOR/p21 signaling pathway by targeting and up-regulating PTEN in human osteosarcoma cells. Hence, imperatorin is a desirable candidate for clinical treatments of osteosarcoma.
Project description:A microarray study including two primary isolated human myoblast cell cultures ( samples A and B) was designed in order to detect the differences in global gene expression during four different culture conditions, two actively proliferating and two non-proliferating. Myoblasts were kept long term proliferating (BG0, before G0) followed by G0 arrest (G0), reactivation (AG0, after G0) and finally they were differentiated (Dif). The samples BG0 and AG0 were harvested when cells reached 70-80% confluence. The raw data from gene arrays were normalized, sample A and B were paired and the mean expression value used for further analyses. The four samples were compared to each other in order to detect differences in gene expression between the samples.
Project description:A microarray study including two primary isolated human myoblast cell cultures ( samples A and B) was designed in order to detect the differences in global gene expression during four different culture conditions, two actively proliferating and two non-proliferating. Myoblasts were kept long term proliferating (BG0, before G0) followed by G0 arrest (G0), reactivation (AG0, after G0) and finally they were differentiated (Dif). The samples BG0 and AG0 were harvested when cells reached 70-80% confluence. The raw data from gene arrays were normalized, sample A and B were paired and the mean expression value used for further analyses. The four samples were compared to each other in order to detect differences in gene expression between the samples. Primary isolated human myoblast cells were cultured through four different culture, BG0, G0, AG0 and Dif. Two independent studies were made with primary isolated myoblasts from two different individuals for each of the four culture condition. Thus the number of samples for microarray analyses was 8.
Project description:Cell size and the cell cycle are intrinsically coupled and abnormal increases in cell size are associated with senescence and permanent cell cycle arrest. The mechanism by which overgrowth primes cells to withdraw from the cell cycle remains unknown. We investigate this here using CDK4/6 inhibitors that arrest cell cycle progression during G0/G1 and are used in the clinic to treat ER+/HER2- metastatic breast cancer. We demonstrate that CDK4/6 inhibition promotes cellular overgrowth during G0/G1, causing p38MAPK-p53-p21-dependent cell cycle withdrawal. We find that cell cycle withdrawal is triggered by two waves of p21 induction. First, overgrowth during a long-term G0/G1 arrest induces an osmotic stress response. This stress response produces the first wave of p21 induction. Second, when CDK4/6 inhibitors are removed, a fraction of cells escape long term G0/G1 arrest and enter S-phase where overgrowth-driven replication stress results in a second wave of p21 induction that causes cell cycle withdrawal from G2, or the subsequent G1. We propose a model whereby both waves of p21 induction contribute to promote permanent cell cycle arrest. This model could explain why cellular hypertrophy is associated with senescence and why CDK4/6 inhibitors have long-lasting effects in patients.
Project description:The development of ovarian follicles constitutes the foundation of female reproduction. The proliferation of granulosa cells (GCs) is a basic process required to ensure normal follicular development. However, the mechanisms involved in controlling GC cell cycle are not fully understood. Here, by performing gene expression profiling, we showed that cell cycle arrest at G0/G1 phase is highly correlated with pathways associated with hypoxic stress and FOXO signalling. Specifically, the elevated proportion of GCs at the arrested G0/G1 phase was accompanied by increased nuclear translocation of FOXO1 under conditions of hypoxia both in vivo and in vitro. Actually, phosphorylation of 14-3-3 by the JNK kinase is required for hypoxia-mediated FOXO1 activation and the resultant G0/G1 arrest. Notably, FOXO1 mutant without DNA-binding activity failed to induce G0/G1 arrest of GCs during hypoxia. Importantly, we identified a new target gene of FOXO1, namely TP53INP1, which contributed to the suppression of the G1-S cell cycle transition in response to hypoxia. Furthermore, we demonstrated that the inhibitory effect of the FOXO1-TP53INP1 axis on GC cell cycle is mediated through a p53-CDKN1A-dependent mechanism. These findings might provide avenues for the clinical treatment of human infertility caused by impaired follicular development.
Project description:Body cells in multi-cellular organisms are in the G0 state, in which cells are arrested and terminally differentiated. To understand how the G0 state is maintained, the genes that are specifically expressed or repressed in G0 must be identified, as they control G0. In the fission yeast Schizosaccharomyces pombe, haploid cells are completely arrested under nitrogen source starvation with high viability. We examined the global transcriptome of G0 cells and cells on the course to resume vegetative growth. Approximately 20% of the transcripts of ~5000 genes increased or decreased more than 4-fold in the two-step transitions that occur prior to replication. Of the top 30 abundant transcripts in G0, 23 were replaced by ribosome- and translation-related transcripts in the dividing vegetative state. Eight identified clusters with distinct alteration patterns of ~2700 transcripts were annotated by Gene Ontology. Disruption of 53 genes indicated that 9 of them were necessary to support the proper G0 state. These 9 genes included two C2H2 zinc finger transcription factors, a cyclin-like protein implicated in phosphorylation of RNA polymerase II, two putative autophagy regulators, a G-protein activating factor, and two CBS domain proteins, possibly involved in AMP-activated kinase. Keywords: Keywards: Time course, Nitrogen starvation, G0 state, Nitrogen replenishment, Nutrient signal, Cell cycle, Cell proliferation
Project description:The miR-16 family, which targets genes important for the G1-S transition, is a known modulator of the cell cycle, and members of this family are often deleted or down-regulated in many types of cancers. Here we report the reciprocal relationship - that of the cell cycle controlling the miR-16 family. Levels of this family increase rapidly as cells are arrested in G0. Conversely, as cells are released from G0 arrest, levels of the miR-16 family rapidly decrease. Such rapid changes are made possible by the unusual instabilities of several family members. The repression mediated by the miR-16 family is sensitive to these cell cycle changes, which suggests that the rapid up-regulation of the miR-16 family reinforces cell cycle arrest in G0. Upon cell cycle re-entry, the rapid decay of several members allows levels of the family to decrease, alleviating repression of target genes and allowing proper resumption of the cell cycle. Small RNAs were profiled by high-throughput sequencing either during synchronous release after serum starvation or during cell-cycle arrest by contact inhibition.
Project description:The miR-16 family, which targets genes important for the G1-S transition, is a known modulator of the cell cycle, and members of this family are often deleted or down-regulated in many types of cancers. Here we report the reciprocal relationship - that of the cell cycle controlling the miR-16 family. Levels of this family increase rapidly as cells are arrested in G0. Conversely, as cells are released from G0 arrest, levels of the miR-16 family rapidly decrease. Such rapid changes are made possible by the unusual instabilities of several family members. The repression mediated by the miR-16 family is sensitive to these cell cycle changes, which suggests that the rapid up-regulation of the miR-16 family reinforces cell cycle arrest in G0. Upon cell cycle re-entry, the rapid decay of several members allows levels of the family to decrease, alleviating repression of target genes and allowing proper resumption of the cell cycle.
Project description:We demonstrate that Polo-like kinase 4(PLK4) is overexpressed in human bladder cancer (BC) cell lines and tissues, and its overexpression correlates with poor prognosis. PLK4 inhibition suppresses BC cell growth and induces G1 phase arrest via activating p38/p53/p21 pathway in vitro and in vivo. The data suggest that PLK4 might serve as a novel molecular target for BC treatment.