Apoptosis In Ovarian Cancer Cells Research Articles

Yamogenin-Induced Cell Cycle Arrest, Oxidative Stress, and Apoptosis in Human Ovarian Cancer Cell Line

Steroidal saponins are a group of compounds with complex structures and biological activities. They have anti-inflammatory, antimicrobial, fungicidal, and antitumor properties. Yamogenin is one of the spirostane saponins and occurs in Trigonella foenum-graecum, Asparagus officinalis, and Dioscorea collettii. It is a stereoisomer of diosgenin-a well-known compound whose activity and mechanisms of action in cancer cells are determined. However, the antitumor effect of yamogenin is still little known, and the mechanism of action has not been determined. In this study, we evaluated the effect of yamogenin on human ovarian cancer SKOV-3 cells in vitro by determining the cellular factors that trigger cell death. The viability of the cells was assessed with a Real-Time xCELLigence system and the cell cycle arrest with flow cytometry. The activity of initiator and executioner caspases (-8, -9, and -3/7) was estimated with luminometry and flow cytometry, respectively. The mitochondrial membrane depolarization, the level of oxidative stress, and DNA damage in the yamogenin-treated cells were also evaluated by flow cytometry. Genes expression analysis at the mRNA level was conducted with Real-Time PCR. Bid activation and chromatin condensation were estimated with fluorescent microscopy. The obtained results indicate that yamogenin has cytotoxic activity in SKOV-3 cells with an IC50 value of 23.90 ± 1.48 µg/mL and strongly inhibits the cell cycle in the sub-G1 phase. The compound also triggers cell death with a significant decrease in mitochondrial membrane potential, an increase in the level of oxidative stress (over two times higher in comparison to the control), and activation of caspase-8, -9, -3/7, as well as Bid. The results of genes expression indicate that the Tumor Necrosis Factor (TNF) Receptor Superfamily Members (TNF, TNFRSF10, TNFRSF10B, TNFRSF1B, and TNFRSF25), Fas Associated via Death Domain (FADD), and Death Effector Domain Containing 2 (DEDD2) were significantly upregulated and their relative expression was at least two times higher than in the control. Our work shows that yamogenin induces apoptosis in ovarian cancer cells, and both the extrinsic and mitochondrial-intrinsic pathways are involved in this process.

Monocytes: A Promising New TRAIL in Ovarian Cancer Cell Therapy.

Adoptive cell transfer of IFN-activated monocytes administered intraperitoneally to patients with platinum-resistant ovarian cancer demonstrated antitumor effects and acceptable tolerability. The exposure of monocytes to IFNα and IFNγ upregulated TRAIL, which triggered caspase 8 and direct cell-to-cell contact-dependent apoptosis of ovarian cancer cells. See related article by Green et al., p. 349.

Maggot Extract Inhibits Cell Migration and Tumor Growth by Targeting HSP90AB1 in Ovarian Cancer.

Ovarian cancer is one of the most lethal gynecological malignancies, because of metastatic dissemination with poor late clinical therapy. Maggots have been used in traditional Chinese medicine, where they are also known as 'Wu Gu Chong'. Previous studies have indicated that maggot extract (ME) was beneficial for the treatment of gastric cancer when combined with other drugs, but the effect on anti-ovarian cancer and the underlying mechanism remains unclear. The aim of this study was to investigate the effects of ME on suppressing the proliferation and migration of ovarian cancer cells, and to clarify the underlying mechanism. In this research, Cell Counting Kit-8 (CCK-8), colony formation assay, and luciferase-positive cell quantification assay were employed to identify the inhibitory effects of ME on cell proliferation. Then, the pro-apoptosis and anti-metastasis effects of ME were explored by Western blot, dual annexin V-fluorescein isothiocyanate/propidium iodide (FITC/PI) assay, immunofluorescent staining, and wound-healing assay. We further established a xenograft model by subcutaneously or intraperitoneally injecting BALB/c nude mice with SKOV3 cells stably expressing luciferase, and the mice were treated with ME. The results showed that ME therapy effectively restrained the growth and metastasis of ovarian tumors in vivo. Furthermore, the mRNA levels of cancer factors including heat shock protein 90 alpha family class B member 1 (HSP90AB1), MYC, and insulin like growth factor 1 receptor (IGF1R) were analyzed by quantitative real-time PCR assay to explore the possible antitumor mechanisms of ME. Next, HSP90 ATPase activity was inhibited by geldanamycin in A2780, and the cell viability was shown to be dramatically reduced, decreasing further with the combination of ME and cisplatin. In turn, HSP90AB1 overexpression effectively inhibited the effect of ME in suppressing capability for cell viability and migration. In addition, HSP90AB1 overexpression limited the ability of ME to inhibit expression of MYC and IGF1R, while the opposite effect was observed for expression of pro-apoptosis protein caspase3 and BAX. Therefore, this study confirmed the potential roles and mechanisms of ME in inhibiting the growth and metastasis of ovarian tumors and promoting apoptosis of ovarian cancer cells by inhibiting overexpression of HSP90AB1.

Adiponectin: A player in the pathogenesis of hormone-dependent cancers.

Hormone-dependent cancers are a major cause of morbidity and mortality in both genders. Accumulating evidence suggest that adiponectin, an adipokine with multifaceted functions, is implicated in the pathogenesis of several malignancies. In the present review, we discuss the existing data regarding this relationship. Several observational studies showed that low adiponectin levels are associated with higher risk for breast, cervical, endometrial, ovarian and prostate cancer. A relationship between adiponectin and the aggressiveness of some of these tumors has also been reported. In vitro studies reported that adiponectin inhibits the proliferation and induces apoptosis of breast, cervical, endometrial, ovarian and prostate cancer cells. Given the high prevalence of these cancers and the substantial associated morbidity and mortality, the role of agents that increase adiponectin levels and/or stimulate its activity should be evaluated for the prevention and management of these common tumors.

Shikonin Mediates Apoptosis through G Protein-Coupled Estrogen Receptor of Ovarian Cancer Cells.

This study was intended to establish the predictive target of Shikonin (SK) against ovarian cancer using network pharmacology and to clarify the potential mechanism of SK in promoting apoptosis in ovarian cancer. Cell Counting Kit-8 assay, plate clone assays, LDH assay, flow cytometric analysis of Annexin V-fluorescein isothiocyanate/propidium iodide staining, and western blotting were used to assess the effect of SK on apoptosis of ovarian cancer cell lines (SKOV3 and A2780). Pharmacodynamic targets were used to predict the targets of SK and ovarian cancer. Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway enrichment analyses were used to analyze the biological functions and signal pathways of these targets. SK promoted apoptosis in ovarian epithelioid adenocarcinoma cells. SK-ovarian cancer pharmacodynamic target analysis screened 17 related genes. GO and KEGG analyses showed that SK affected the estrogen signaling pathway. SK inhibited the expression of GPER in SKOV3 and A2780 cells and downregulated the expression of EGFR, p-EGFR, PI3K, and p-AKT in a concentration-dependent manner. The apoptosis-promoting effect of SK was enhanced by GPER-specific agonist G1 and inhibited by the specific inhibitor G15. The expression of EGFR, p-EGFR, PI3K, and p-AKT was decreased by G1 and reversed by G15. SK also inhibited tumor growth in the SKOV3 xenograft model, and it acted synergistically with G1. However, the effect can be attenuated by G15 in vivo. In summary, SK may affect the apoptosis of ovarian cancer cells through GPER/EGFR/PI3K/AKT, and GPER may be a key target of SK in ovarian cancer cell apoptosis.

Linifanib induces apoptosis in human ovarian cancer cells via activation of FOXO3 and reactive oxygen species

Linifanib is known as an inhibitor of receptor tyrosine kinase. Even though it has been widely recognized as efficient inhibitor of receptor tyrosine kinases, anti-carcinogenic effect has not been investigated enough in ovarian cancer. In this study, we investigated the anti-cancer effect of linifanib on human ovary cancer SKOV3 cells. WST-1, cell counting assay, and observation of morphological changes were performed to evaluate the cytotoxic effect of linifanib in SKOV3 cells. We analyzed SKOV3 cells treated with linifanib using Muse cell analyzer. We focused on investigating the effect of linifanib on DNA damage in nucleus. Additionally, intracellular reactive oxygen species (ROS) level was measured through Muse cell analyzer. Western blotting was performed to evaluate the protein expression level related to apoptosis. We found that linifanib inhibited proliferation of SKOV3 cells. Our results showed that linifanib induced apoptosis in SKOV3 cells. Additionally, linifanib induced DNA damage in SKOV3 cells. We found that intracellular ROS level increased after treatment of linifanib in SKOV3 cells. Interestingly, FOXO3 was transferred from cytosol into nucleus after linifanib treatment. Taken together, our results supported that linifanib inhibited the proliferation of human ovary cancer SKOV3 cells, which suggested that linifanib might have the potential to be developed as drugs for ovarian cancer treatment.

Memantine enhances the cisplatin-induced apoptosis in A2780 ovarian cancer cells via CyclinD1 and hTERT inhibition

Cisplatin is the first-line treatment for ovarian cancer. Therefore, the use of effective compounds with synergistic effects can be considered a new strategy. Memantine is an NMDA receptors blocker which is overexpressed in cancers, including ovarian cancer and thus can be an efficient adjunct in cancer treatment. In this study, the MTT test, Flow cytometry, and DAPI staining was used to examine the combined effect of cisplatin with memantine. A study on Cyclin D1 and hTERT expression levels were conducted by qRT-PCR, and also cell cycle study of treated cells was performed. Our findings demonstrated that memantine enhances cytotoxicity in A2780 ovarian cancer cells. Apoptosis was also enhanced in cells treated with the combination of memantine and cisplatin. Memantine reduced the expression of Cyclin D1 and hTERT in A2780 cells and decreased the number of cancer cells in the cell cycle's growth and division phase. Our study suggests that memantine can be considered a potent adjuvant in the treatment of ovarian cancer.

PUMA overexpression dissociates thioredoxin from ASK1 to activate the JNK/BCL-2/BCL-XL pathway augmenting apoptosis in ovarian cancer

ASK1-JNK signaling promotes mitochondrial dysfunction-mediated apoptosis, but the bridge between JNK and apoptosis is not fully understood. PUMA induces apoptosis through BAX/BAK. Our previous study suggests a therapeutic potential of PUMA for ovarian cancer. However, whether and how PUMA activates ASK1 remains unclear. Here, we found for the first time that PUMA activated ASK1 by dissociating thioredoxin (TRX) from ASK1, however, it neither interacted with ASK1 nor TRX. Furthermore, PUMA overexpression caused ROS release from mitochondrial. H2O2 significantly impaired the interaction of ASK1 with TRX, whereas ROS scavenger NAC effectively abrogated the H2O2 effect, partly rescued PUMA-interfered interaction of ASK1 with TRX, and also abolished ASK1 phosphorylation. Interestingly, PUMA could not impair the association of ASK1 with TRX-C32S or TRX-C35S, two TRX mutants which are no longer oxidized in response to ROS. We further showed that PUMA activated ASK1-JNK axis to phosphorylate BCL-2 and BCL-XL, further augmenting apoptosis of ovarian cancer cells. In vivo, PUMA adenovirus combined with paclitaxel significantly inhibited intrinsically cisplatin-resistant ovarian cancer growth, and caused phosphorylation of BCL-2 and BCL-XL. Our results from human ovarian cancer TMA chips also revealed a positive correlation between PUMA expression and the phosphorylation of BCL-2 and BCL-XL. More importantly, all patients had no distal metastasis, implying a possibly clinical significance. Collectively, our results reveal a new pro-apoptotic signal amplification mechanism for PUMA by which PUMA overexpression first induces ROS-mediated dissociation of TRX from ASK1, and then causes JNK activation-triggering BCL-2/BCL-XL phosphorylation, ultimately augmenting apoptosis in ovarian cancer.

Engineered water-soluble photosensitive fluorescent probes of β-galactosidase with fast response based on triarylboron compound derivatives for ovarian cancer cell imaging

β-Galactosidase is a primary biomarker for ovarian cancer, which poses a serious threat to the health of women. Herein, we report the design and synthesis of three fluorescent probes for β-galactosidase based on triarylboron (TAB): TAB-2-Gal, TAB-4-Gal, and TAB-6-Gal. The performance of these probes was tuned by changing their structure. They demonstrate excellent water solubility and fast responses, superior to most of the previously reported properties of existing β-galactosidase probes. In particular, using TAB-4-Gal the entire recognition process can be completed within 4 min and this probe produces the greatest fluorescence signal. As TAB-4-Gal possesses a piperazine group in its structure, it better able to locate lysosomes and produces a strong fluorescence signal from ovarian cancer cells. Thus, it is an ideal fluorescent probe for distinguishing ovarian cancer cells from other cells. Moreover, the high photosensitivity of TAB-4-Gal means that it can also selectively induce apoptosis of ovarian cancer cells under low-intensity visible light irradiation (1.5 mW/cm2).

Dihydroquercetin (DHQ) has the potential to promote apoptosis in ovarian cancer cells: An in silico and in vitro study

Ovarian cancer is the third leading gynaecological malignancy that leads to death in females annually. According to the GLOBOCAN 2020 incidence cases in Asia, there were a total of 100,854 ovarian cancer incidence cases. The Food and Drug Administration (FDA) has approved some drug compounds from both the generic and pharmaceutical brands for ovarian cancer, however, these synthetic compounds have many adverse effects such as – infections, fatigue, nerve problems, alopecia (hair loss), weight loss, lack of appetite, chemobrain (forgetfulness). By exploring both the in silico and in vitro aspects, we suggest that dihydroquercetin (DHQ) or simply taxifolin is an effective herbal compound that is druggable, leadlike, has good bioavailability, medicinal chemistry with a higher solubility with no adverse side effects, and toxicity. It also showcased a greater and more stable binding affinity and energy landscape with target POTEE with minimal energy frustrations and clashes. Our study also was able to predict a positive classification model of DHQ with a Tanimoto-distance threshold (d0 = 0.8) and smoothing factor (h = 0.9). We observed that the accuracy decreases to 90% from 100% at distance = 0.7, predicted number of compounds rose from 80 to 95%, which can be worth the loss of accuracy. Furthermore, our in vitro analysis on SK-OV-3 cell lines showcased that the anticancerous activity of DHQ caused significant cancer cell death and cell proliferation at 100 µm and 250 µm solutions. The DHQ drug dosages were further verified by Calcein-AM-PI live dead cell imaging on both concentrations. We observed that at 250 µm, DHQ caused apoptosis in SK-OV-3 cells. Hence, it is concluded that DHQ reduces ovarian cell proliferation and eventually cell death (apoptosis) in ovarian cancer.

Circ_0061140 Contributes to Ovarian Cancer Progression by Targeting miR-761/LETM1 Signaling.

Previous studies have suggested that circular RNAs (circRNAs) play important regulatory roles in cancer progression. Previous evidence exhibited the aberrant upregulation of circ_0061140 in ovarian cancer. However, the detailed role of circ_0061140 in ovarian cancer progression and its associated mechanism remain largely unknown and need further exploration. The expression of circ_0061140, microRNA-761 (miR-761) and leucine zipper and EF-hand containing transmembrane protein 1 (LETM1) was checked by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) or western blot. Cell Counting Kit-8 (CCK8), colony formation, 5-Ethynyl-2'-deoxyuridine (EdU), flow cytometry, wound healing, transwell, and tube formation assays were conducted to assess cell functions. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were performed to confirm the interaction between miR-761 and circ_0061140 or LETM1. Xenograft tumor model was established to analyze the role of circ_0061140 in tumor growth in vivo. Circ_0061140 expression was notably up-regulated in ovarian cancer tissues and cell lines. Circ_0061140 knockdown suppressed the proliferation, migration, invasion, and angiogenesis and triggered the apoptosis of ovarian cancer cells. Circ_0061140 directly interacted with miR-761, and circ_0061140 silencing-mediated anti-tumor effects were partly abolished by miR-761 knockdown in ovarian cancer cells. LETM1 was a direct target of miR-761, and LETM1 overexpression partly counteracted miR-761-induced anti-tumor effects. Circ_0061140 could up-regulate LETM1 expression by sponging miR-761. Circ_0061140 knockdown significantly suppressed xenograft tumor growth in vivo. Circ_0061140 aggravated ovarian cancer progression through miR-761-dependent regulation of LETM1.

Synergetic effect of poly (ADP-ribosyl) polymerase (PARP) inhibitor and cisplatin on ovarian cancer

Purpose: To investigate the effect of the combination of poly (ADP-ribosyl) polymerase (PARP) inhibitor, talazoparib (BMN673), and cisplatin on the proliferation and apoptosis of ovarian cancer cells in vitro, and on xenograft tumors of ovarian cancer cells in vivo.
 Methods: Cell viability was determined by CCK-8 assay, while cell proliferation and cell cycle were assessed using colony formation assay and flow cytometry, respectively. Cell apoptosis was evaluated by flow cytometry and TUNEL assays. Western blot assay was used to measure the expression levels of proliferation- and apoptosis-related proteins.
 Results: The PARP inhibitor, BMN673, produced a dose-dependent synergistic effect with cisplatin (p < 0.05). Compared with when cisplatin or BMN673 was used alone, the combination of cisplatin and BMN673 significantly inhibited the growth of transplanted tumors (p < 0.05). Immunohistochemical analysis showed that cisplatin and BMN673 treatment increased the number of cells positive for TUNEL, but reduced the population of cells positive for Ki67.
 Conclusion: Thus, BMN673 and cisplatin are synergistic against ovarian cancer cells, and therefore, should be subjected to further investigations, including clinical trials, to determine the potentials of the combination for the management of ovarian carcinoma.
 Keywords: PARP inhibitor; Ovarian cancer; Xenografted tumor; Cisplatin

Breaking the Iron Homeostasis: A "Trojan Horse" Self-Assembled Nanodrug Sensitizes Homologous Recombination Proficient Ovarian Cancer Cells to PARP Inhibition.

Poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitors are used in ovarian cancer treatment and have greatly improved the survival rates for homologous recombination repair (HRR)-deficient patients. However, their therapeutic efficacy is limited in HRR-proficient ovarian cancer. Thus, sensitizing HRR-proficient ovarian cancer cells to PARP inhibitors is important in clinical practice. Here, a nanodrug, olaparib-Ga, was designed using self-assembly of the PARP inhibitor olaparib into bovine serum albumin through gallic acid gallium(III) coordination via a convenient and green synthetic method. Compared with olaparib, olaparib-Ga featured an ultrasmall size of 7 nm and led to increased suppression of cell viability, induction of DNA damage, and enhanced cell apoptosis in the SKOV3 and OVCAR3 HRR-proficient ovarian cancer cells in vitro. Further experiments indicated that the olaparib-Ga nanodrug could suppress RRM2 expression, activate the Fe2+/ROS/MAPK pathway and HMOX1 signaling, inhibit the PI3K/AKT signaling pathway, and enhance the expression of cleaved-caspase 3 and BAX protein. This, in turn, led to increased cell apoptosis in HRR-proficient ovarian cancer cells. Moreover, olaparib-Ga effectively restrained SKOV3 and OVCAR3 tumor growth and exhibited negligible toxicity in vivo. In conclusion, we propose that olaparib-Ga can act as a promising nanodrug for the treatment of HRR-proficient ovarian cancer.

Identification and biotin receptor-mediated activity of a novel seleno-biotin compound that inhibits viability of and induces apoptosis in ovarian cancer cells

A series of seleno-biotin analogs were synthesized and their anticancer activity and mode of action were assessed using ovarian cancer cells. Compound 2, out of the other analogs, in direct comparison to biotin alone, more effectively reduced the cell viability and induced apoptosis in ovarian cancer cell lines in a dose dependent manner as demonstrated by the cell viability assay, trypan blue dye exclusion assay, Annexin V/7-AAD, and Caspase 3/7 apoptosis assays. Furthermore, compound 2 showed efficacy better than 5-fluorouracil (5-FU) and similar to cisplatin, in vitro; notably it was more cytotoxic to drug-resistant Hey A8 cells than cisplatin. The cytotoxicity of compound 2 was primarily mediated by reactive oxygen species (ROS) as demonstrated by DCFDA based ROS estimation. Biotin receptors (BR) saturation and the use of a BR negative cell line showed a significant decline in the cytotoxic ativity of the compound 2, confirming that its activity is BR-mediated. These experiments demonstrated that selenium modified biotin which contains an ester linked redox cycling selenocyanate group has the potential for human therapeutic applications against ovarian and other cancers over-expressing BR.

TRIM37 promotes the aggressiveness of ovarian cancer cells and increases c-Myc expression by binding to HUWE1

Tripartite motif containing 37 (TRIM37) was reported to function as a tumor promoter in the development of various cancers. However, the biological role of TRIM37 in ovarian cancer (OC) was still unclear. Expressions of TRIM37 and HUWE1 were detected by qRT-PCR and western blotting in OC cells. Cell proliferation was evaluated by CCK-8 assay and colony formation assay. Cell migration and invasion capabilities were examined by wound healing and transwell assay. Flow cytometry and western blotting were performed to measure cell apoptosis. Wnt/β-catenin pathway and the expression of c-Myc were identified by qRT-PCR and western blotting. The binding of TRIM37 and HUWE1 was predicted by STRING database and verified by co-immunoprecipitation. In addition, a xenograft mouse model was established to evaluate the effects of TRIM37 and HUWE1 on tumor growth and c-MYC expression in vivo. The present study revealed that TRIM37 expression was upregulated in OC tissues and cells. TRIM37 silencing inhibited OC cell migration and invasion, promoted OC cell apoptosis, and blocked Wnt/β-catenin signaling pathway, as well as suppressing c-MYC protein expression. Mechanistic studies suggested that TRIM37 binds to HUWE1. HUWE1 was upregulated in OC cells and TRIM37 promoted the c-MYC expression through targeting HUWE1. Animal experiments showed that TRIM37 silencing significantly repressed the tumor growth and c-MYC protein level, but HUWE1 overexpression reversed the effects of TRIM37 knockdown on mice with OC. Our findings revealed that TRIM37 accelerated the progression of OC and promoted c-MYC expression by binding to HUWE1, which provides therapeutic targets for OC treatment.

Circular RNA circPBX3 promotes cisplatin resistance of ovarian cancer cells via interacting with IGF2BP2 to stabilize ATP7A mRNA expression.

Circular RNAs (circRNAs) are a class of non-coding RNAs with a unique covalently closed loop structure. Recent studies indicate that dysregulation of circRNAs acts a role in cancer progression and chemotherapy resistance via interacting with RNA-binding proteins (RBPs). Herein, we identified circPBX3 to be involved in cisplatin resistance of ovarian cancer. In our study, two cisplatin-resistant ovarian cancer cell lines were established, and transcriptome RNA-sequencing was performed and circPBX3 was identified as significantly upregulated circRNA in these cells. The characteristics of circPBX3 and potential function of circPBX3 were evaluated. We found that circPBX3 was upregulated in ovarian tumor tissues and cisplatin-resistant ovarian cancer cells. CircPBX3 overexpression increased the half maximal inhibitory rate (IC50) of cisplatin, promoted colony formation and tumor xenografts growth, and reduced cell apoptosis of ovarian cancer cells under cisplatin treatment, while silencing circPBX3 showed opposite effects. Furthermore, circPBX3 could interact with the RNA-binding protein IGF2BP2, thus increased the stability of ATP7A mRNA and elevated ATP7A protein level. In addition, silencing ATP7A in ovarian cancer cells abrogated the effect of circPBX3 overexpression on cisplatin tolerance. Our findings provided a novel role of circPBX3 in cisplatin resistance of ovarian cancer.

Retro-inversion follicle-stimulating hormone peptide-modified nanoparticles for delivery of PDK2 shRNA against chemoresistant ovarian cancer by switching glycolysis to oxidative phosphorylation

BackgroundMost ovarian cancers are diagnosed at advanced stages characterized by abdominal dissemination and frequently exhibit chemoresistance. Pyruvate dehydrogenase kinase 2 (PDK2) regulates the switch between glycolysis and oxidative phosphorylation and contributes to tumor progression and chemoresistance. Here, we investigated the effects of PDK2 blockade on metabolic reprogramming and cisplatin sensitivity and evaluated the in vivo antitumor effects of PDK2 shRNA in chemoresistant ovarian cancer using retro-inverso follicle-stimulating hormone peptide-modified nanoparticle as carriers.MethodsThe expression of PDK2 was detected by immunohistochemistry, Western blot and real-time PCR. Cell proliferation and apoptosis were detected using CCK-8 and flow cytometry. Cell migration was detected by Transwell assay. Seahorse Analyzer was used to evaluate metabolic changes. The cisplatin-resistant ovarian cancer cells A2780cp were used to establish the mouse model of peritoneal metastatic ovarian cancer.ResultsA higher expression level of PDK2 was observed in chemoresistant ovarian cancer tissues and cell lines and was associated with shorter progression-free survival. PDK2 knockdown inhibited proliferation and migration and promoted apoptosis of both cisplatin-sensitive and cisplatin-resistant ovarian cancer cells. Cisplatin sensitivity was increased even in cisplatin-resistant ovarian cancer cells. Mechanistically, PDK2 knockdown resulted in an increased oxygen consumption rate and decreased extracellular acidification rate, along with reduced lactate production, increased PDHC activity and increased levels of electron transport chain complexes III and V. The metabolism switched from glycolysis to oxidative phosphorylation. Finally, to specifically and effectively deliver PDK2 shRNA in vivo, we formulated a targeted delivery system containing retro-inverso follicle-stimulating hormone peptide as a targeting moiety and polyethylene glycol–polyethylenimine copolymers as carriers. The nanoparticle complex significantly suppressed tumor growth and peritoneal metastasis of cisplatin-resistant ovarian cancer without obvious toxicities.ConclusionsOur findings showed the link between metabolic reprogramming and chemoresistance in ovarian cancer and provided an effective targeting strategy for switching metabolic pathways in cancer therapy.

CpG-binding protein CFP1 promotes ovarian cancer cell proliferation by regulating BST2 transcription

Epigenetic alterations have been functionally linked to ovarian cancer development and occurrence. The CXXC zinc finger protein 1 (CFP1) is an epigenetic regulator involved in DNA methylation and histone modification in mammalian cells. However, its role in ovarian cancer cells is unknown. Here, we show that CFP1 protein is highly expressed in human ovarian cancer tissues. Loss of CFP1 inhibited the growth of human ovarian cancer cells, promoted apoptosis, and increased senescence. CFP1 knockdown resulted in reduced levels of SETD1 (a CFP1 partner) and histone H3 trimethylation at the fourth lysine residue (H3K4me3). RNA-sequencing revealed that deletion of CFP1 resulted in mRNA reduction of bone marrow stromal cell antigen 2 (BST2). Bioinformatics analysis and chromatin immunoprecipitation showed that CFP1 binds to the promoter of BST2 and regulates its transcription directly. Overexpression of BST2 rescued the growth inhibitory effect of CFP1 loss. Furthermore, depletion of cullin-RING ubiquitin ligases 4 (CRL4) components ROC1 or CUL4A had significantly inhibited the expression of CFP1 and BST2 similar to MLN4924 treatment that blocked cullin neddylation and inactivated CRL4s. In conclusion, CFP1 promotes ovarian cancer cell proliferation and apoptosis by regulating the transcription of BST2, and the expression of CFP1 was affected by CRL4 ubiquitin ligase complex.

Icariside II suppresses the tumorigenesis and development of ovarian cancer by regulating miR-144-3p/IGF2R axis.

Ovarian cancer is one of the three major gynecological malignancies. It has been reported that Icariside II was able to block the occurrence and development of ovarian cancer. However, the detailed mechanism by which Icariside II regulates the development of ovarian cancer is widely unknown. EdU staining and transwell assays were applied to detect the proliferation, migration, and invasion of ovarian cancer cells. Next, the relationship between miR-144-3p and IGF2R was verified by the dual-luciferase reporter assay. Moreover, in vivo animal model was constructed to verify the effect of Icariside II on the development of ovarian cancer. Icariside II notably inhibited the proliferation, migration, and invasion and induced the apoptosis of ovarian cancer cells. Additionally, Icariside II markedly increased the level of miR-144-3p in ovarian cancer cells. Moreover, IGF2R was targeted by miR-144-3p directly. Icariside II significantly decreased the expression of IGF2R and the phosphorylation level of AKT and mTOR in ovarian cancer cells, which were partially reversed by miR-144-3p inhibitor. Meanwhile, Icariside II remarkably promoted the autophagy of ovarian cancer cells, as confirmed by the increased expression of Beclin-1 and ATG-5 and decreased expression of p62; however, co-treatment with miR-144-3p inhibitor notably decreased autophagy. Furthermore, the result of animal study suggested Icariside II notably inhibited ovarian tumor growth as well. Collectively, Icariside II could suppress the tumorigenesis and development of ovarian cancer by promoting autophagy via miR-144-3p/IGF2R axis. These results may be beneficial for future studies on the use of Icariside II to treat ovarian cancer.

ERCC5 abnormal expression influences the biological behaviour of ovarian cancer by Wnt pathway

Nucleotide excision repair (NER) is the most important repair pathway of DNA, and a variety of cancers are closely related to the gene abnormal expression and the deletion or downregulation of gene function in NER pathway. In this study, we investigated the differential expression of ERCC5 in different ovarian cancer cells and its potential mechanism. By detecting the expression of ovarian in both SKOV3 and Caov4 cell lines, we found that the expression of ERCC5 in SKOV3 was significantly higher than that in Caov4. We further constructed the SKOV3 cell line with low ERCC5 expression by RNA interference and Caov4 cell line with high ERCC5 expression by transient transfection, then comparing the effect of ERCC5 abnormal expression on the biological behaviour of ovarian cancer cells. The results showed that high expression of ERCC5 could significantly promote proliferation and migration of ovarian cancer but inhibit apoptosis. However, low expression of ERCC5 could significantly promote apoptosis but inhibited proliferation and migration. We further observed the effect of ERCC5 abnormal expression on potential regulation pathway by Western blot and noticed that ERCC5 abnormal expression could activate the Wnt pathway. Overall, the results revealed that ERCC5 abnormal expression could influence the proliferation, apoptosis and migration ability of ovarian cancer cells by activating the Wnt pathway.