anisomycin and Ovarian-Neoplasms

Angiogenesis has an important role in tumour cell growth and metastasis. Anisomycin has been shown to inhibit tumour cell growth. However, whether anisomycin can inhibit angiogenesis of tumours has not been reported. The present study demonstrated that there was a positive correlation between tumour angiogenesis and the number of CD44+/CD133+ serous human ovarian cancer stem cells (HuOCSCs). Subsequently, it was confirmed that anisomycin significantly inhibited the proliferation, invasion, tumorigenic ability and tumour angiogenesis of HuOCSCs. Gene expression profiling by cDNA microarrays revealed that the expression levels of vascular endothelial cell markers, platelet‑derived growth factors, Notch pathway components and 27 tumour angiogenesis‑related genes were significantly decreased in the anisomycin‑treated group compared with the control group. Further experiments demonstrated that the expression levels of endogenous long non‑coding RNA (lncRNA) maternally expressed 3 (Meg3) were significantly decreased in anisomycin‑treated HuOCSCs, whereas the expression levels of microRNA (miR)‑421 were significantly increased. The results of luciferase reporter assays indicated that, when miR‑421 was overexpressed in cells, the luciferase activities of wild‑type platelet derived growth factor receptor α (PDGFRA) 3' untranslated region and Meg3 reporter plasmids were significantly decreased. Overexpression of miR‑421 in HuOCSCs significantly enhanced the anisomycin‑mediated inhibition of HuOCSC proliferation. Taken together, the present results demonstrated that anisomycin inhibited the activation downstream of the Notch1 pathway by attenuating the molecular sponge effect of the lncRNA‑Meg3/miR‑421/PDGFRA axis, ultimately inhibiting angiogenesis, proliferation and invasion in ovarian cancer cells.

Topics: 3' Untranslated Regions; Animals; Anisomycin; Carcinogenesis; Carcinoma, Ovarian Epithelial; Cell Proliferation; Drug Screening Assays, Antitumor; Embryo, Nonmammalian; Female; Gene Expression Regulation, Neoplastic; Humans; Mice; MicroRNAs; Neoplasm Invasiveness; Neoplastic Stem Cells; Neovascularization, Pathologic; Neovascularization, Physiologic; Ovarian Neoplasms; Ovary; Primary Cell Culture; Receptor, Platelet-Derived Growth Factor alpha; RNA, Long Noncoding; Tumor Cells, Cultured; Xenograft Model Antitumor Assays; Zebrafish

Human ovarian cancer stem cells (OCSCs) are one of the main factors affecting ovarian cancer cell metastasis, recurrence, prognosis and tolerance to chemotherapy drugs. However, the mechanisms of OCSC proliferation and invasion are not clear. Recent studies suggest that anisomycin can inhibit the proliferative and invasive ability of various tumor cells by increasing the production of the toxic amyloid β (Aβ1-42) peptides from the amyloid precursor protein (APP). We explored whether anisomycin could also suppress human OCSC proliferation and invasion. The CD44+/CD117+ OCSCs were enriched from human clinical ovarian tumor tissues. OCSCs treated with anisomycin showed reduced proliferation compared to controls. Moreover, anisomycin significantly suppressed the invasive capacity of OCSCs in vitro, as indicated by cell migration assays. The mRNA expression levels of long non-coding RNA (lncRNA) β-site APP cleaving enzyme 1 antisense strand (BACE1-AS) were significantly increased in anisomycin-treated OCSCs compared to controls. In addition, mRNA and protein levels of BACE1 and Aβ1-42 were increased in anisomycin-treated OCSCs compared to controls. We confirmed that anisomycin suppressed the growth of xenograft tumors formed by OCSCs in vivo. Finally, when expression of lncRNA BACE1-AS was silenced using siRNA, BACE1 expression was downregulated and the antiproliferative and anti-invasive effects of anisomycin were reduced. Overall, we identified lncRNA BACE1-AS as a novel target for anisomycin. Elevation of lncRNA BACE1-AS expression is a potential mechanism for suppressing human OCSC proliferation and invasion.

Topics: Adult; Animals; Anisomycin; Cell Line, Tumor; Cell Proliferation; Female; Humans; Mice; Middle Aged; Neoplasm Invasiveness; Neoplastic Stem Cells; Ovarian Neoplasms; RNA, Long Noncoding; Up-Regulation; Xenograft Model Antitumor Assays

Cisplatin (DDP)-resistance confers a deficient expression of spermidine/spermine N(1)-acetyltransferase (SSAT) gene in response to the spermine analog N(1),N(12)-bis(ethyl)spermine (BESpm) in the DDP-resistant human ovarian carcinoma cell line (C13*), compared with their parental DDP-sensitive 2008 cells. This SSAT gene deficiency is correlated with a reduced growth sensitivity to spermine analogs. This study was performed to determine whether SSAT gene expression of resistant cells was kept suppressed by labile repressor proteins developed during resistance selection. We show here that inhibitory concentrations of cycloheximide (CHX) and anisomycin (ANISO) differentially affect BESpm-induced SSAT activity in 2008 and in C13* cells in a concentration-dependent manner and allow resistant cells to reach activation levels comparable to those of the sensitive cells. Northern blot analysis revealed that both CHX and ANISO in combination with BESpm caused a synergistic BESpm-mediated accumulation of SSAT mRNA in C13* cells, with respect to each drug alone, while in 2008 cells only a slight increase was observed. The more pronounced effect of inhibitors on the SSAT activity induced by BESpm in the resistant cells was also the result of a more prolonged stabilization of SSAT mRNA and enzyme protein. By contrast, sub-inhibitory concentrations of CHX and ANISO did not significantly stimulate BESpm-induced SSAT transcription and activity. These results suggest that labile repressor proteins, related to DDP-resistance phenotype, play a regulatory role in SSAT gene expression, and further indicate that by overcoming this inhibitory control it is possible to recover BESpm response.

Topics: Acetyltransferases; Anisomycin; Antineoplastic Agents; Carcinoma; Cell Line, Tumor; Cisplatin; Cycloheximide; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Drug Synergism; Female; Gene Expression Regulation, Neoplastic; Humans; Ovarian Neoplasms; Protein Synthesis Inhibitors; RNA, Messenger; Spermine

Calcium signaling has been linked to activation of Pyk2, a calcium-dependent, focal adhesion kinase-related, non-receptor tyrosine kinase. Signaling via Pyk2 can activate c-jun NH(2)-terminal kinase (JNK). Calcium has also been shown to activate phosphatidylinositol triphosphate kinase and/or JNK. Here, we show that calcium signaling in ovarian surface epithelial cells not only induces telomerase activity via JNK but also activates Pyk2. Moreover, telomerase activation by Pyk2 requires JNK activation. In contrast, a kinase-deficient Pyk2 construct failed to activate either JNK or telomerase. Finally, we demonstrate that Pyk2 is capable of driving the human telomerase reverse transcriptase promoter, resulting in telomerase activation. These data suggest a novel role of Pyk2 for telomerase regulation.

Topics: Anisomycin; Calcium; Cell Line; Chromones; DNA-Binding Proteins; Edetic Acid; Enzyme Induction; Enzyme Inhibitors; Epithelial Cells; Female; Focal Adhesion Kinase 2; Humans; JNK Mitogen-Activated Protein Kinases; Mitogen-Activated Protein Kinases; Morpholines; Ovarian Neoplasms; Ovary; Phosphatidylinositol 3-Kinases; Protein-Tyrosine Kinases; Recombinant Proteins; Telomerase; Transfection; Tumor Cells, Cultured

Telomerase activity is present in >90% of all tumors and appears to be regulated by the phosphatidylinositol 3-kinase signaling pathway. Here we demonstrate that Akt is not involved in the signaling cascade for telomerase regulation in ovarian surface epithelial cells. However, we showed that c-Jun NH2-kinase induces telomerase activity, that inhibition of JNK by JIP abrogates telomerase activity, and that JNK expression activates transcription of a reporter gene fused to the hTERT promoter sequence. Consequently, our data show that JNK is a key regulator of telomerase activity and, hence, may provide new perspectives on tumorigenesis that could be exploited for novel therapeutic strategies.

Topics: Anisomycin; DNA-Binding Proteins; Enzyme Induction; Epithelial Cells; Female; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Humans; JNK Mitogen-Activated Protein Kinases; Mitogen-Activated Protein Kinases; Ovarian Neoplasms; Phosphatidylinositol 3-Kinases; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; RNA, Messenger; Telomerase; Transcription, Genetic; Transcriptional Activation; Transfection; Tumor Cells, Cultured