Manner In Ovarian Cancer Cells Research Articles

M6A-driven NAT10 translation facilitates fatty acid metabolic rewiring to suppress ferroptosis and promote ovarian tumorigenesis through enhancing ACOT7 mRNA acetylation.

RNA epigenetic modifications have been implicated in cancer progression. However, the interplay between distinct RNA modifications and its role in cancer metabolism remain largely unexplored. Our study demonstrates that N-acetyltransferase 10 (NAT10) is notably upregulated in ovarian cancer (OC), correlating with poor patient prognosis. IGF2BP1 enhances the translation of NAT10 mRNA in an m6A-dependent manner in OC cells. NAT10 drives tumorigenesis by mediating N4-acetylcytidine (ac4C) modification of ACOT7 mRNA, thereby augmenting its stability and translation. This NAT10-ACOT7 axis modulates fatty acid metabolism in cancer cells and promotes tumor progression by suppressing ferroptosis. Additionally, our research identifies fludarabine as a small molecule inhibitor targeting NAT10, inhibits the ac4C modification and expression of ACOT7 mRNA. By using cell derived xenograft model and patient derived organoid model, we show that fludarabine effectively suppresses ovarian tumorigenesis. Overall, our study highlights the pivotal role of the NAT10-ACOT7 axis in the malignant cancer progression, underscoring the potential of targeting NAT10-mediated ac4C modification as a viable therapeutic strategy for this disease.

Purified Vitexin Compound 1 Serves as a Promising Antineoplastic Agent in Ovarian Cancer.

Ovarian cancer is a common gynecologic aggressive neoplasm. The mortality of ovarian cancer is top among gynecologic malignancies due to the insidious onset, atypical early symptoms, and chemoresistance. Therefore, it is urgent to seek another promising treatment for ovarian cancer. Purified vitexin compound 1 (VB1) is a kind of neolignan from the seed of traditional Chinese herb vitex negundo that possessed diverse pharmacological effects. VB1 can exhibit anti-neoplastic activities against various cancers. However, the role of VB1 in ovarian cancer treatment has not been elaborated, and the mechanism is unknown. The aim of this study was to investigate the therapeutic effects of VB1 in ovarian cancer cells both in vitro and in vivo, along with the molecular mechanism of action. In vitro, VB-1 can effectively suppress the proliferation, induce apoptosis, and block cell cycle at G2/M phase with a concentration dependent manner in ovarian cancer cells. Western blot assay showed that VB1 induce apoptosis via upregulating expression of cleaved-caspase3 and block cell cycle at G2/M phase through upregulating expression of P21. Meanwhile, VB1 can effectively inhibit tumor growth in xenograft mouse model. Our research indicated that VB1 can significantly exert its anti-neoplastic effects and may represent a new class of agents in ovarian cancer therapy.

Beta-Caryophyllene Suppresses Ovarian Cancer Proliferation by Inducing Cell Cycle Arrest and Apoptosis.

Ovarian cancer is the fifth most common cause of cancer deaths among women with lesser prognostics. Current treatment options are chemotherapy with platinum and taxane based chemotherapy. β-Caryophyllene (BCP) an essential oil found in many plant species is known to possess an anti-proliferative effect. We aimed to investigate the antiproliferative, cytotoxic, and apoptotic role of BCP against ovarian cancer cells PA-1 and OAW 42. The antiproliferative effect of BCP was determined by MTT assay and cell viability by trypan blue exclusion assay. Cell cycle and live/dead cell analyses were performed by flow cytometry to determine cell cycle distribution and apoptosis, respectively. Results of MTT assay proved the anti-proliferative effect of BCP in a dose and time-dependent manner in ovarian cancer cells. Cell cycle analysis showed that BCP induced S Phase arrest in OAW 42 cells. Results of apoptosis assay confirmed the apoptosis inducing potential of BCP in ovarian cancer cells. The apoptosis is mediated by caspase-3 activation and PARP cleavage. The results of our present study prove that BCP exerts its action partly by inducing cell cycle arrest and apoptosis in ovarian cancer. We conclude that BCP is a potential anti-cancer agent.

Zinc regulates primary ovarian tumor growth and metastasis through the epithelial to mesenchymal transition

BackgroundThe trace element zinc plays an indispensable role in human health and diseases including cancer due to its antioxidant properties. While zinc supplements have been used for cancer prevention, zinc is also a risk factor for cancer development. It is still unclear how zinc plays a role in ovarian cancer. MethodsTo understand how zinc contributes to ovarian tumor growth and metastasis, we examined whether zinc contributes to tumor metastasis by regulating epithelial to mesenchymal transition (EMT) using ovarian cancer cells in vitro. Cell migration and invasion were examined using transwell plates and EMT markers were examined using Western blot. Primary ovarian tumor growth and metastasis were assessed using orthotopic ovarian cancer mouse models in vivo. ResultsZinc promoted EMT, while TPEN (N, N, N’, N’-tetrakis-(2-pyridylmethyl)-ethylenediamine), a membrane-permeable selective zinc chelator, inhibited EMT in a dose dependent manner in ovarian cancer cells. Moreover, zinc promoted ovarian cancer cell migration and invasion, while TPEN inhibited cell migration and invasion. Zinc activated expression of the metal response transcriptional factor-1 (MTF-1), while TPEN inhibited MTF-1 expression in a dose dependent manner. Knockout of MTF-1 inhibited zinc-induced cell migration, invasion and augmented the inhibitory effect of TPEN on cell migration and invasion. Loss of MTF-1 attenuated zinc-induced ERK1/2 and AKT activation and augmented the effect of TPEN in attenuating the ERK1/2 and AKT pathways. TPEN effectively inhibited primary ovarian tumor growth and metastasis in an orthotopic ovarian cancer mouse model by suppressing EMT. Conclusionzinc contributes to ovarian tumor metastasis by promoting EMT through a MTF-1 dependent pathway. Zinc depletion by TPEN may be a novel approach for ovarian cancer therapy by inhibiting EMT and attenuating the ERK1/2 and AKT pathways.

Tanshinone I attenuates the malignant biological properties of ovarian cancer by inducing apoptosis and autophagy via the inactivation of PI3K/AKT/mTOR pathway.

ObjectivesTanshinone I (Tan‐I) is one of the vital fatsoluble monomer components, which extracted from Chinese medicinal herb Salvia miltiorrhiza Bunge. It has been shown that Tan‐I exhibited anti‐tumour activities on different types of cancers. However, the underlying mechanisms by which Tan‐Ⅰ regulates apoptosis and autophagy in ovarian cancer remain unclear. Thus, this study aimed to access the therapy effect of Tan‐Ⅰ and the underlying mechanisms.MethodsOvarian cancer cells A2780 and ID‐8 were treated with different concentrations of Tan‐Ⅰ (0, 1.2, 2.4, 4.8 and 9.6 μg/mL) for 24 hours. The cell proliferation was analysed by CCK8 assay, EdU staining and clone formation assay. Apoptosis was assessed by the TUNEL assay and flow cytometry. The protein levels of apoptosis protein (Caspase‐3), autophagy protein (Beclin1, ATG7, p62 and LC3II/LC3I) and PI3K/AKT/mTOR pathway were determined by Western blot. Autophagic vacuoles in cells were observed with LC3 dyeing using confocal fluorescent microscopy. Anti‐tumour activity of Tan‐Ⅰ was accessed by subcutaneous xeno‐transplanted tumour model of human ovarian cancer in nude mice. The Ki67, Caspase‐3 level and apoptosis level were analysed by immunohistochemistry and TUNEL staining.ResultsTan‐Ⅰ inhibited the proliferation of ovarian cancer cells A2780 and ID‐8 in a dose‐dependent manner, based on CCK8 assay, EdU staining and clone formation assay. In additional, Tan‐Ⅰ induced cancer cell apoptosis and autophagy in a dose‐dependent manner in ovarian cancer cells by TUNEL assay, flow cytometry and Western blot. Tan‐Ⅰ significantly inhibited tumour growth by inducing cell apoptosis and autophagy. Mechanistically, Tan‐Ⅰ activated apoptosis‐associated protein Caspase‐3 cleavage to promote cell apoptosis and inhibited PI3K/AKT/mTOR pathway to induce autophagy.ConclusionsThis is the first evidence that Tan‐Ⅰ induced apoptosis and promoted autophagy via the inactivation of PI3K/AKT/mTOR pathway on ovarian cancer and further inhibited tumour growth, which might be considered as effective strategy.

Interactions of Omentin and Lactotransferrin in the Progression of Metastatic Ovarian Cancer

Advanced stage serous ovarian cancer metastasizes preferentially to the omentum, which is a major site of intra‐abdominal fat accumulation and is covered by a layer of mesothelial cells (mesothelium). Ovarian cancer cells first adhere to and then penetrate through the mesothelium. It was previously shown the expression of adipokine omentin (ITLN1) in mesothelial cells was down‐regulated when mesothelial cells were co‐cultured with ovarian cancer cells. Survival correlation studies demonstrated that patients with serum ITLN1 levels of >350 ng/mL at the time of first treatment experienced longer survival times than those with lower levels of ITLN1. In addition, wound‐healing assay and invasion assay demonstrated that ovarian cancer cells (SKOV3 and A224) treated with physiological levels of ITLN1 showed a significant decrease in motility and invasion potential. However, the molecular mechanism by which ITLN1 modulates these malignant phenotypes remains unknown. Cancer cells migrate using cell‐matrix mechanocoupling mechanisms through paths generated by the degradation and remodeling of the extracellular matrix (ECM) and by force‐mediated deformation (powered by cell traction force from cancer cells). To explore whether omentin suppresses ovarian cancer invasion potential via inhibiting ECM proteolysis, RNA sequencing and pathway analyses were performed on ITLN1 treated cancer cells. Significantly lower levels of MMP1 (matrix metalloproteinase‐1) was found in cancer cells treated with ITLN1 than untreated cells, which was confirmed by qRT‐PCR analysis. Since ITLN1 has been shown to interact with LTF (lactotransferrin), and binding of LTF to its receptors LRP1 (low‐intensity lipoprotein‐receptor‐related protein 1) can transcriptionally upregulate MMP1, an in vitro pull‐down assay on purified LTF and recombinant ITLN1 in serum‐free media was first performed to confirm that ITLN1 interacts and binds with LTF. To determine whether ITLN1 can interfere with the binding of LTF to LRP1 on ovarian cancer cells, a Duolink proximity ligation assay was performed using both anti‐LTF and anti‐LRP1 antibodies. There was a significant decrease in fluorescent signals in cells that were treated with ITLN1 compared to the control. The results suggested that ITLN1 interacts with LTF and prevents LTF from binding to its receptor LRP1 on ovarian cancer cells. Furthermore, ITLN1 abrogated the effects of LTF on MMP1 expression in a dose‐dependent manner in ovarian cancer cells. LTF not only induced MMP1 expression, but also triggered an increase of cytosolic Ca2+ and cell traction force in ovarian cancer cells, which were attenuated by pre‐incubation with ITLN1. Taken together, these data suggest that ITLN1 suppressed LTF's effect on the motility and invasion potential of ovarian cancer cells by decreasing MMP1 expression and cell traction force generation through modulating a calcium dependent LTF‐LRP1 signaling pathway.Support or Funding InformationDepartment of Defense: grant W81XWH‐17‐1‐0146This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Expression of Concern: "Aurora-A induces cell survival and chemoresistance by activation of Akt through a p53-dependent manner in ovarian cancer cells" by Hua Yang, Lili He, Patricia Kruk, Santo V. Nicosia and Jin Q. Cheng.

Expression of Concern: "Aurora-A induces cell survival and chemoresistance by activation of Akt through a p53-dependent manner in ovarian cancer cells" by Hua Yang, Lili He, Patricia Kruk, Santo V. Nicosia and Jin Q. Cheng.

DR2 blocker thioridazine: A promising drug for ovarian cancer therapy.

Dopamine receptor 2 (DR2) may be a biomarker for various types of cancer. Ovarian cancer cells overexpress DR2; therefore, blocking DR2 may be a novel treatment strategy for ovarian cancer. Thioridazine, a DR2 blocker, has antineoplastic activity in a variety of cancer cells. In view of the requirement for novel therapeutic agents in ovarian cancer, the present study aimed to determine the potential effects of thioridazine in vitro and in vivo. It was revealed that the DR2 blocker thioridazine induced cell death in a dose-dependent manner in ovarian cancer cells. Thioridazine treatment induced apoptosis and autophagy, which may be attributed to an increased level of reactive oxygen species and associated DNA damage. Additionally, the expression of various proteins increased with oxidative stress, including nuclear factor E2-related factor 2, which is a pivotal transcriptional factor involved in cellular responses to oxidative stress. Heme oxygenase 1, NAPDH quinone dehydrogenase 1 and hypoxia inducible factor-1α and phosphorylated (p)-protein kinase B expression was significantly decreased, and the expression level of p-extracellular signal-related kinases and p-P38 was increased. Using 3-methyl adenine to inhibit autophagy caused the rate of apoptosis to increase. Thioridazine inhibited the growth of SKOV3 xenografts in nude mice. The present study demonstrated that the DR2 blocker thioridazine exhibited anticancer effects in vitro and in vivo, suggesting that thioridazine may be used as a potential drug in ovarian cancer therapy.

Iron alters cell survival in a mitochondria-dependent pathway in ovarian cancer cells.

The role of iron in the development of cancer remains unclear. We previously reported that iron reduces cell survival in a Ras/mitogen-activated protein kinase (MAPK)-dependent manner in ovarian cells; however, the underlying downstream pathway leading to reduced survival was unclear. Although levels of intracellular iron, ferritin/CD71 protein and reactive oxygen species did not correlate with iron-induced cell survival changes, we identified mitochondrial damage (via TEM) and reduced expression of outer mitochondrial membrane proteins (translocase of outer membrane: TOM20 and TOM70) in cell lines sensitive to iron. Interestingly, Ru360 (an inhibitor of the mitochondrial calcium uniporter) reversed mitochondrial changes and restored cell survival in HEY ovarian carcinoma cells treated with iron. Further, cells treated with Ru360 and iron also had reduced autophagic punctae with increased lysosomal numbers, implying cross-talk between these compartments. Mitochondrial changes were dependent on activation of the Ras/MAPK pathway since treatment with a MAPK inhibitor restored expression of TOM20/TOM70 proteins. Although glutathione antioxidant levels were reduced in HEY treated with iron, extracellular glutamate levels were unaltered. Strikingly, oxalomalate (inhibitor of aconitase, involved in glutamate production) reversed iron-induced responses in a similar manner to Ru360. Collectively, our results implicate iron in modulating cell survival in a mitochondria-dependent manner in ovarian cancer cells.

Iron modulates cell survival in a Ras- and MAPK-dependent manner in ovarian cells

Ovarian cancer is a leading cause of cancer death in women in the United States. While the majority of ovarian cancers are serous, some rarer subtypes (i.e. clear cell) are often associated with endometriosis, a benign gynecological disease. Iron is rich in the cyst fluid of endometriosis-associated ovarian cancers and induces persistent oxidative stress. The role of iron, an essential nutrient involved in multiple cellular functions, in normal ovarian cell survival and ovarian cancer remains unclear. Iron, presented as ferric ammonium citrate (FAC), dramatically inhibits cell survival in ovarian cancer cell types associated with Ras mutations, while it is without effect in immortalized normal ovarian surface epithelial (T80) and endometriotic epithelial cells (lacking Ras mutations). Interestingly, FAC induced changes in cytoplasmic vacuolation concurrently with increases in LC3-II levels (an autophagy marker); these changes occurred in an ATG5/ATG7-dependent, beclin-1/hVps34-independent, and Ras-independent manner. Knockdown of autophagy mediators in HEY ovarian cancer cells reversed FAC-induced LC3-II levels, but there was little effect on reversing the cell death response. Intriguingly, transmission electron microscopy of FAC-treated T80 cells demonstrated abundant lysosomes (confirmed using Lysotracker) rich in iron particles, which occurred in a Ras-independent manner. Although the mitogen-activated protein kinase (MAPK) inhibitor, U0126, reversed FAC-induced LC3-II/autophagic punctae and lysosomes in a Ras-independent manner, it was remarkable that U0126 reversed cell death in malignant ovarian cells associated with Ras mutations. Moreover, FAC increased heme oxygenase-1 expression in H-Ras-overexpressing T80 cells, which was associated with increased cell death when overexpressed in T80 cells. Disruption of intracellular iron levels, via chelation of intracellular iron (deferoxamine), was also detrimental to malignant ovarian cell survival; thus, homeostatic intracellular iron levels are essential for cell survival. Collectively, our results implicate iron in modulating cell death in a Ras- and MAPK-dependent manner in ovarian cancer cells.

Aspirin Blocks EGF-stimulated Cell Viability in a COX-1 Dependent Manner in Ovarian Cancer Cells

Objective: Although aspirin has been associated with a reduction of the risk of cancer when used as a nonsteroidal anti-inflammatory drug, its use to reduce the risk of ovarian cancer is controversial. Ovarian cancer cells usually express high levels of cyclooxygenase-1 (COX)-1. Because aspirin is a rather selective inhibitor of COX-1, the ability of aspirin to reduce the risk of ovarian cancer may be dependent on the level of COX-1 expression in those cells. Furthermore, epidermal growth factor receptor (EGFR) is frequently overexpressed in the malignant phenotype of ovarian cancer leading to increased cell proliferation and survival. Here we investigated if aspirin attenuates EGFR-activated ovarian cancer cell growth in a COX-1 dependent manner.Methods: Cell viability assays and Western blot analyses were used to determine the effect of aspirin on EGF-stimulated cell proliferation. Gene silencing and gene expression techniques were employed to knockdown or to express COX-1, respectively.Results: Aspirin inhibited cell viability induced by EGF in a dose dependent manner in COX-1 positive ovarian cancer cells. On the other hand, aspirin had no effect on cell viability in COX-1 negative ovarian cancer cells. In particular, aspirin decreased phosphorylated Akt and Erk activated by EGF. COX-1 silencing in COX-1 positive cells attenuated the inhibitory effect of aspirin on EGF-stimulated cell viability. Furthermore, we developed a COX-1 expressing cell line (SKCOX-1) by stably transfecting COX-1 expression vector into COX-1 negative SKOV-3 cells. SKCOX-1 cells were more responsive to aspirin when compared to cells transfected with empty vector, and decreased EGF-activated Akt and Erk as well as cell viability.Conclusions: Taken together, aspirin inhibits viability of ovarian cancer cells by blocking phosphorylation of Akt and Erk activated by EGF. Thus it may potentiate the therapeutic efficacy of drugs used to treat COX-1 positive ovarian cancer subsets.

Aurora‐A induces cell survival and chemoresistance by activation of Akt through a p53‐dependent manner in ovarian cancer cells

Aurora-A is frequently altered in epithelial malignancies. Overexpressing Aurora-A induces centrosome amplification and G2/M cell cycle progression. We have previously shown elevated level of Aurora-A in ovarian cancer and activation of telomerase by Aurora-A in human mammary and ovarian epithelia. Here we report that Aurora-A protects ovarian cancer cells from apoptosis induced by chemotherapeutic agent and activates Akt pathway in a p53-dependent manner. Ectopic expression of Aurora-A renders cells resistant to cisplatin (CDDP), etoposide and paclitaxel-induced apoptosis and stimulates Akt1 and Akt2 activity in wild-type p53 but not p53-null ovarian cancer cells. Aurora-A inhibits cytochrome C release and Bax conformational change induced by CDDP. Knockdown of Aurora-A by RNAi sensitizes cells to CDDP-induced apoptosis and decreases phospho-Akt level in wild-type p53 cells. Reintroduction of p53 decreases Akt1 and Akt2 activation and restores CDDP sensitivity in p53-null but not p53-null-Aurora-A cells. Inhibition of Akt by small molecule inhibitor, API-2, overcomes the effects of Aurora-A-on cell survival and Bax mitochondrial translocation. Taken collectively, these data indicate that Aurora-A activates Akt and induces chemoresistance in a p53-dependent manner and that inhibition of Akt may be an effective means of overcoming Aurora-A-associated chemoresistance in ovarian cancer cells expressing wild-type p53.