Targeting polyploid giant cancer cells potentiates a therapeutic response and overcomes resistance to PARP inhibitors in ovarian cancer.

To understand the mechanism of acquired resistance to poly(ADP-ribose) polymerase inhibitors (PARPi) olaparib, we induced the formation of polyploid giant cancer cells (PGCCs) in ovarian and breast cancer cell lines, high-grade serous cancer (HGSC)-derived organoids, and patient-derived xenografts (PDXs). Time-lapse tracking of ovarian cancer cells revealed that PGCCs primarily developed from endoreplication after exposure to sublethal concentrations of olaparib. PGCCs exhibited features of senescent cells but, after olaparib withdrawal, can escape senescence via restitutional multipolar endomitosis and other noncanonical modes of cell division to generate mitotically competent resistant daughter cells. The contraceptive drug mifepristone blocked PGCC formation and daughter cell formation. Mifepristone/olaparib combination therapy substantially reduced tumor growth in PDX models without previous olaparib exposure, while mifepristone alone decreased tumor growth in PDX models with acquired olaparib resistance. Thus, targeting PGCCs may represent a promising approach to potentiate the therapeutic response to PARPi and overcome PARPi-induced resistance.

Activity-based protein profiling reveals active serine proteases that drive malignancy of human ovarian clear cell carcinoma.

Ovarian clear cell carcinoma (OCCC) is an understudied poor prognosis subtype of ovarian cancer lacking in effective targeted therapies. Efforts to define molecular drivers of OCCC malignancy may lead to new therapeutic targets and approaches. Among potential targets are secreted proteases, enzymes which in many cancers serve as key drivers of malignant progression. Here, we found that inhibitors of trypsin-like serine proteases suppressed malignant phenotypes of OCCC cell lines. To identify the proteases responsible for malignancy in OCCC, we employed activity-based protein profiling to directly analyze enzyme activity. We developed an activity-based probe featuring an arginine diphenylphosphonate warhead to detect active serine proteases of trypsin-like specificity and a biotin handle to facilitate affinity purification of labeled proteases. Using this probe, we identified active trypsin-like serine proteases within the complex proteomes secreted by OCCC cell lines, including two proteases in common, tissue plasminogen activator and urokinase-type plasminogen activator. Further interrogation of these proteases showed that both were involved in cancer cell invasion and proliferation of OCCC cells and were also detected in in vivo models of OCCC. We conclude the detection of tissue plasminogen activator and urokinase-type plasminogen activator as catalytically active proteases and significant drivers of the malignant phenotype may point to these enzymes as targets for new therapeutic strategies in OCCC. Our activity-based probe and profiling methodology will also serve as a valuable tool for detection of active trypsin-like serine proteases in models of other cancers and other diseases.

CaMKK2 Promotes the Progression of Ovarian Carcinoma through the PI3K/PDK1/Akt Axis.

Objective: To explore the functional role of Calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2) in the progression of ovarian carcinoma (OC). Methods: RT-qPCR analysis and western blot were conducted to detect the mRNA and protein expression of CaMKK2, PI3K, PDK1 and Akt in OC tissues and cells, respectively. CCK-8 assay, transwell migration assay and flow cytometry were used to measure cell proliferation, migration and apoptosis, respectively. Results: CaMKK2, PI3K, PDK1 and Akt were highly expressed in OC tissues compared with the corresponding controls. CaMKK2 knockdown significantly suppressed the mRNA and protein expression of PI3K, PDK1 and Akt in HO8910 and OV90 cells. Moreover, CaMKK2 knockdown could dramatically repress cell proliferation, migration, and markedly elevate cell apoptosis in HO8910 and OV90 cells. Conclusions: CaMKK2 played a promotion role in OC progression via activating the PI3K/PDK1/Akt axis.

AKR1C1/2 inhibition by MPA sensitizes platinum resistant ovarian cancer towards carboplatin.

In recurrent epithelial ovarian cancer (EOC) most patients develop platinum-resistance. On molecular level the NRF2 pathway, a cellular defense mechanism against reactive oxygen species, is induced. In this study, we investigate AKR1C1/2, target of NRF2, in a well-established EOC collective by immunohistochemistry and in a panel of ovarian cancer cell lines including platinum-resistant clones. The therapeutic effect of carboplatin and MPA as monotherapy or in combination was assessed by functional assays, using OV90 and OV90cp cells. Molecular mechanisms of action of MPA were investigated by NRF2 silencing and AKR activity measurements. Immunohistochemical analysis revealed that AKR1C1/2 is a key player in the development of chemoresistance and an independent indicator for short PFS (23.5 vs. 49.6 months, p = 0.013). Inhibition of AKR1C1/2 by MPA led to a concentration- and time-dependent decline of OV90 viability and to an increased response to CP in vitro. By NRF2 silencing, however, the effects of MPA treatment were reduced. Concludingly, our data suggest that a combination therapy of carboplatin and MPA might be a promising therapeutic approach to increase response rates of EOC patients, which should be explored in clinical context.

ST6Gal-I-mediated sialylation of the epidermal growth factor receptor modulates cell mechanics and enhances invasion.

Heterogeneity within the glycocalyx influences cell adhesion mechanics and signaling. However, the role of specific glycosylation subtypes in influencing cell mechanics via alterations of receptor function remains unexplored. It has been shown that the addition of sialic acid to terminal glycans impacts growth, development, and cancer progression. In addition, the sialyltransferase ST6Gal-I promotes epidermal growth factor receptor (EGFR) activity, and we have shown EGFR is an 'allosteric mechano-organizer' of integrin tension. Here, we investigated the impact of ST6Gal-I on cell mechanics. Using DNA-based tension gauge tether probes of variable thresholds, we found that high ST6Gal-I activity promotes increased integrin forces and spreading in Cos-7 and OVCAR3, OVCAR5, and OV4 cancer cells. Further, employing inhibitors and function-blocking antibodies against ß1, ß3, and ß5 integrins and ST6Gal-I targets EGFR, tumor necrosis factor receptor, and Fas cell surface death receptor, we validated that the observed phenotypes are EGFR-specific. We found that while tension, contractility, and adhesion are extracellular-signal-regulated kinase pathway-dependent, spreading, proliferation, and invasion are phosphoinositide 3-kinase-Akt serine/threonine kinase dependent. Using total internal reflection fluorescence microscopy and flow cytometry, we also show that high ST6Gal-I activity leads to sustained EGFR membrane retention, making it a key regulator of cell mechanics. Our findings suggest a novel sialylation-dependent mechanism orchestrating cellular mechanics and enhancing cell motility via EGFR signaling.

Caffeic acid phenethyl ester targets ubiquitin-specific protease 8 and synergizes with cisplatin in endometrioid ovarian carcinoma cells.

Deubiquitinases (DUBs) mediate the removal of ubiquitin from diverse proteins that participate in the regulation of cell survival, DNA damage repair, apoptosis and drug resistance. Previous studies have shown an association between activation of cell survival pathways and platinum-drug resistance in ovarian carcinoma cell lines. Among the strategies available to inhibit DUBs, curcumin derivatives appear promising, thus we hypothesized their use to enhance the efficacy of cisplatin in ovarian carcinoma preclinical models. The caffeic acid phenethyl ester (CAPE), inhibited ubiquitin-specific protease 8 (USP8), but not proteasomal DUBs in cell-free assays. When CAPE was combined with cisplatin in nine cell lines representative of various histotypes a synergistic effect was observed in TOV112D cells and in the cisplatin-resistant IGROV-1/Pt1 variant, both of endometrioid type and carrying mutant TP53. In the latter cells, persistent G1 accumulation upon combined treatment associated with p27kip1 protein levels was observed. The synergy was not dependent on apoptosis induction, and appeared to occur in cells with higher USP8 levels. In vivo antitumor activity studies supported the advantage of the combination of CAPE and cisplatin in the subcutaneous model of cisplatin-resistant IGROV-1/Pt1 ovarian carcinoma as well as CAPE activity on intraperitoneal disease. This study reveals the therapeutic potential of CAPE in cisplatin-resistant ovarian tumors as well as in tumors expressing USP8.

Anti-oncogenic PTEN induces ovarian cancer cell senescence by targeting P21.

Deletion and mutation of phosphatase and tensin homolog deleted on chromosome10 (PTEN) are closely associated with the occurrence of tumors. Tumor suppressor gene PTEN mutation plays an important role in the pathogenesis of ovarian cancer. However, it has been unclear whether it can regulate the senescence of ovarian cancer cells. We speculated that PTEN might inhibit the occurrence and development of ovarian cancer by promoting the expression of P21. We found that the expression of TRIM39 in human ovarian cancer was significantly diminished. In SKOV3 cells treated with naringin, the expression of TRIM39, which binds P21 and inhibits P21 degradation, was significantly elevated. Real-time polymerase chain reaction (PCR), Western blot, and immunofluorescence were used to detected the expression of PTEN, p21, and TRIM39, ß-galactosidase Staining was used to detect cell senescence, Ki67 staining was used to observe cell proliferation, Trim39 interference or overexpression assay was used to detect its function. We speculated that PTEN might promote SKOV3 cell senescence by increasing TRIM39 expression and decreasing P21 degradation. Furthermore, by interfering with TRIM39 in SKOV3 cells, we found that the expression of P21 was downregulated, and the number of senescent SKOV3 cells decreased. With overexpression of TRIM39 in SKOV3 cells, the expression of P21 was upregulated, and the number of senescent SKOV3 cells increased. When naringin, a PTEN agonist, was added to SKOV3 cells in which TRIM39 protein was interfered with, the expression of P21 was significantly lower than that in the control group, and the number of senescent ovarian cancer cells was significantly diminished. Our results indicated that PTEN maintained the stability of P21 and decreased the degradation of P21 by increasing TRIM39 expression, thus promoting the senescence of SKOV3 cells, and PTEN maintained the stability of p21 and promoted the aging of SKOV3 cells might be a novel therapeutic target for ovarian cancer.

RNA assay identifies a previous misclassification of BARD1 c.1977A>G variant.

Case-control studies have shown an association of BARD1 with hereditary breast and/or ovarian cancer (HBOC) predisposition. BARD1 alternatively spliced isoforms are abundant and some are highly expressed in different cancer types. In addition, a number of BARD1 germline pathogenic variants have been reported among HBOC patients. In previous reports, BARD1 c.1977A>G variant has been classified as pathogenic since it produces a frameshift transcript lacking exons 2 to 9. In the present study, we sought to validate the mRNA splicing results previously published and to contribute with new evidence to refine the classification of this substitution according to ACMG/AMP guidelines. The presence of the variant was screened in patients and controls. RT-PCR was performed in order to compare the transcriptional profiles of two variant carriers and ten non-carrier controls. In addition, allele-specific expression was assessed. No differences in variant frequency were detected between patients and controls. The RNA assay confirmed the presence of the shorter transcript lacking exons 2-9, but it was detected both in carriers and non-carriers. Furthermore, allelic imbalance was discarded and no significant differences in the proportion of full-length and shorter transcript were detected between carriers and controls. The shorter transcript detected corresponds to BARD1 isoform η, constituted by exons 1, 10 and 11. Our results support that this transcript is a constitutive splicing product rather than an aberrant transcript caused by BARD1 c.1977A>G variant, and for this reason this variant should be considered as likely benign following ACMG/AMP guidelines.

Prognostic role of USP7 expression in cancer patients: A systematic review and meta-analysis.

BACKGROUND: Numerous studies have examined the prognostic value of ubiquitin-specific protease 7 (USP7) in cancer, but the results remain controversial. Differences in assessment assays (mRNA/protein) used could be a potential confounding factor. Thus, we extracted studies that measured the protein expression and performed a meta-analysis to assess the prognostic role of USP7 expression in cancer and to identify clinicopathological features associated with USP7 expression. METHODS: PubMed, Scopus, Web of Science Core Collection, Wiley Online Library, and Google Scholar were searched from inception to July 2020. Pooled hazard ratios were calculated to evaluate the association between USP7 expression and overall survival (OS). In addition, pooled odds ratios were calculated to identify clinicopathological features associated with USP7 expression. RESULTS: Eight studies in China were included in our meta-analysis, which had a total of 1192 patients and assessed five types of cancer. The pooled results revealed that a high expression of USP7 was associated with poor OS, especially in epithelial ovarian cancer (EOC). Moreover, USP7 expression was increased in patients with tumour-node-metastasis (TNM) stages III-IV, poor pathological grade, and positive lymph node metastasis. For patients with EOC, a high USP7 expression positively correlated with lymph node metastasis. CONCLUSION: A high USP7 expression may promote cancer progression and predict unfavourable prognosis of cancer patients, especially those with EOC. Our findings suggest that USP7 inhibitors might be promising therapeutics for cancer patients with such characteristics.

Evaluation of Micro Satellite Instability and Mismatch Repair Status in Different Solid Tumors: A Multicenter Analysis in a Real World Setting.

Immune-checkpoint inhibitors (ICIs) play a key role in the treatment of advanced stage colorectal cancer (CRC) patients featuring a deficient DNA mismatch repair (dMMR) system or a high microsatellite instability (MSI-H) profile. However, beyond the established role in CRC patients, ICIs have highly proven efficacy in other solid tumors featuring MSI-H/dMMR status represented by endometrial, gastric, ovarian, prostatic, and pancreatic carcinomas (EC, GC, OC, PrC, and PaC). Our aim was to compare the concordance rates among the Idylla™ MSI test, TapeStation 4200, and immunohistochemical (IHC) analysis in assessing MSI-H/dMMR status in EC, GC, OC, PrC, and PaC patients. The Sanger sequencing-based Titano MSI test was used in discordant cases. One hundred and eighty-five cases (n = 40 PrC, n = 39 GC, n = 38 OC, n = 35 PaC, and n = 33 EC) were retrospectively selected. MMR protein expression was evaluated by IHC. After DNA quality and quantity evaluations, the IdyllaTM and TapeStation 4200 platforms were adopted for the evaluation of MSI status. Remarkably, compared to IHC, the Idylla™ platform achieved a global concordance rate of 94.5% (154/163) for the microsatellite stable (MSS)/proficient MMR (pMMR) cases and 77.3% (17/22) for the MSI-H/dMMR cases. Similarly, a global concordance rate of 91.4% (149/163) and 68.2% (15/22) for MSS/pMMR and MSI-H/dMMR cases was also identified between IHC and the TapeStation 4200 microfluidic system. In addition, a global concordance of 93.1% (148/159) and 69.2% (18/26) for MSS/pMMR and MSI-H/dMMR cases was observed between the Idylla™ and TapeStation 4200 platforms. Discordant cases were analyzed using the Titano MSI kit. Overall, our data pinpointed a central role for molecular techniques in the diagnostic evaluation of dMMR/MSI-H status not only in CRC patients but also in other types of solid tumors.

Anaplastic Lymphoma Kinase Overexpression Is Associated with Aggressive Phenotypic Characteristics of Ovarian High-Grade Serous Carcinoma.

Deregulated full-length anaplastic lymphoma kinase (ALK) overexpression has been found in some primary solid tumors, but little is known about its role in ovarian high-grade serous carcinoma (HGSC). The current study focused on the functional roles of ALK in HGSC. Cytoplasmic ALK immunoreactivity without chromosomal rearrangement and gene mutations was significantly higher in HGSC compared with non-HGSC-type ovarian carcinomas, and was significantly associated with several unfavorable clinicopathologic factors and poor prognosis. HGSC cell lines stably overexpressing ALK exhibited increased cell proliferation, enhanced cancer stem cell features, and accelerated cell mobility, whereas these phenotypes were abrogated in ALK-knockdown cells. Expression of the nervous system-associated gene, ELAVL3, and the corresponding protein (commonly known as HuC) was significantly increased in cells overexpressing ALK. Expression of SRY-box transcription factor (Sox)2 and Sox3 (genes associated with the neural progenitor population) increased in ALK-overexpressing but not ALK-knockdown cells. Furthermore, overexpression of Sox2 or Sox3 enhanced both ALK and ELAVL3 promoter activities, suggesting the existence of ALK/Sox/HuC signaling loops. Finally, ALK overexpression was attributed to increased expression of neuroendocrine markers, including synaptophysin, CD56, and B-cell lymphoma 2, in HGSC tissues. These findings suggest that overexpression of full-length ALK may influence the biological behavior of HGSC through cooperation with ELAVL3 and Sox factors, leading to the establishment and maintenance of the aggressive phenotypic characteristics of HGSC.

Modelling the Functions of Polo-Like Kinases in Mice and Their Applications as Cancer Targets with a Special Focus on Ovarian Cancer.

Polo-like kinases (PLKs) belong to a five-membered family of highly conserved serine/threonine kinases (PLK1-5) that play differentiated and essential roles as key mitotic kinases and cell cycle regulators and with this in proliferation and cellular growth. Besides, evidence is accumulating for complex and vital non-mitotic functions of PLKs. Dysregulation of PLKs is widely associated with tumorigenesis and by this, PLKs have gained increasing significance as attractive targets in cancer with diagnostic, prognostic and therapeutic potential. PLK1 has proved to have strong clinical relevance as it was found to be over-expressed in different cancer types and linked to poor patient prognosis. Targeting the diverse functions of PLKs (tumor suppressor, oncogenic) are currently at the center of numerous investigations in particular with the inhibition of PLK1 and PLK4, respectively in multiple cancer trials. Functions of PLKs and the effects of their inhibition have been extensively studied in cancer cell culture models but information is rare on how these drugs affect benign tissues and organs. As a step further towards clinical application as cancer targets, mouse models therefore play a central role. Modelling PLK function in animal models, e.g., by gene disruption or by treatment with small molecule PLK inhibitors offers promising possibilities to unveil the biological significance of PLKs in cancer maintenance and progression and give important information on PLKs' applicability as cancer targets. In this review we aim at summarizing the approaches of modelling PLK function in mice so far with a special glimpse on the significance of PLKs in ovarian cancer and of orthotopic cancer models used in this fatal malignancy.

MiR-198 inhibits proliferation, invasion and migration of ovarian cancer cells by regulating the PI3K/Akt signaling pathway.

OBJECTIVE: The specific objective of this investigation is to explore the impact of miR-198 on proliferation, migration as well as invasion of ovarian cancer (OC) cells. METHODS: OC tissue and adjacent normal tissue samples from OC patients were collected, and normal human ovarian epithelial cell IOSE80 and OC cell lines SKOV3, Caov3, A2780 and OVCAR3 were selected in this study for investigation. MiR-198 expression level was assessed using RT-qPCR. MTT, colony formation assay, Transwell and wound healing assay, and flow cytometry were adopted to analyze the role of miR-198 in OVCAR cell proliferation, invasion, migration, as well as apoptosis. Meanwhile, the levels of P13K/Akt signaling pathway-related proteins were determined by western blotting. RESULTS: A significant decrease in miR-198 level was revealed in the OC tissues and cells, contributing to the promotion of OVCAR3 cells in terms of proliferation, migration, invasion, and inhibition of apoptosis. MiR-198 overexpression had an opposite effect on these biological processes of OVCAR3 cells. Further study found that down-regulation of miR-198 caused a significant increase in the activity of PI3K/Akt signaling pathway in the OVCAR3 cells. In contrast, overexpressed miR-198 led to inhibition of this pathway's activity. CONCLUSION: MiR-198 may possess an ability to inhibit activation of the P13K/Akt pathway, thus suppressing the OC cell proliferation, migration, as well as invasion.

Overexpression of RIPK4 Predicts Poor Prognosis and Promotes Metastasis in Ovarian Cancer.

This study was conducted to evaluate the prognostic value of receptor-interacting protein kinase 4 (RIPK4) in ovarian cancer (OC) and its role in tumorigenesis. RNA expression and the corresponding clinical data were obtained from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases. The relationship between clinical-pathological characteristics and RIPK4 expression was analyzed using the Wilcoxon signed-rank test and logistic regression. The Cox regression and the Kaplan-Meier method were used to evaluate the relationship between clinicopathological features and overall survival (OS). Gene set enrichment analysis (GSEA) was performed using Molecular Signatures Database. Scratch assay, transwell assay, and cell transfection were used to verify the function of RIPK4. Overexpression of RIPK4 was associated with the stage of OC and distant metastasis. Survival analysis revealed that patients with OC and higher expression of RIPK4 had a poorer prognosis. Univariate and multivariate analyses indicated that high expression of RIPK4 was associated with poor OS, as well as age and stage of OC. The areas under the curve (AUC) at 1, 4, and 8 years were 0.737, 0.634, and 0.669, respectively, according to the established OS prediction model. GSEA revealed that adherens junction, cadherin binding, and Wnt signaling pathway were enriched in the high RIPK4 expression group. Cell transfection confirmed RIPK4 was involved in the Wnt signaling pathway. RIPK4 can act as a potential prognostic molecular marker for poor survival in OC. Moreover, RIPK4 is associated with tumor metastasis and implicated in the regulation of the Wnt signaling pathway.

Neutrophils drive endoplasmic reticulum stress-mediated apoptosis in cancer cells through arginase-1 release.

Human neutrophils constitutively express high amounts of arginase-1, which depletes arginine from the surrounding medium and downregulates T-cell activation. Here, we have found that neutrophil arginase-1, released from activated human neutrophils or dead cells, induced apoptosis in cancer cells through an endoplasmic reticulum (ER) stress pathway. Silencing of PERK in cancer cells prevented the induction of ER stress and apoptosis. Arginase inhibitor Nω-hydroxy-nor-arginine inhibited apoptosis and ER stress response induced by conditioned medium from activated neutrophils. A number of tumor cell lines, derived from different tissues, were sensitive to neutrophil arginase-1, with pancreatic, breast, ovarian and lung cancer cells showing the highest sensitivity. Neutrophil-released arginase-1 and arginine deprivation potentiated the antitumor action against pancreatic cancer cells of the ER-targeted antitumor alkylphospholipid analog edelfosine. Our study demonstrates the involvement of neutrophil arginase-1 in cancer cell killing and highlights the importance and complex role of neutrophils in tumor surveillance and biology.

Specific Pyruvate Kinase M2 Inhibitor, Compound 3K, Induces Autophagic Cell Death through Disruption of the Glycolysis Pathway in Ovarian Cancer Cells.

Ovarian cancer is a common cause of death among gynecological cancers. Although ovarian cancer initially responds to chemotherapy, frequent recurrence in patients remains a therapeutic challenge. Pyruvate kinase M2 (PKM2) plays a pivotal role in regulating cancer cell survival. However, its therapeutic role remains unclear. Here, we investigated the anticancer effects of compound 3K, a specific PKM2 inhibitor, on the regulation of autophagic and apoptotic pathways in SK-OV-3 (PKM2-overexpressing human ovarian adenocarcinoma cell line). The anticancer effect of compound 3K was examined using MTT and colony formation assays in SK-OV-3 cells. PKM2 expression was positively correlated with the severity of the tumor, and expression of pro-apoptotic proteins increased in SK-OV-3 cells following compound 3K treatment. Compound 3K induced AMPK activation, which was accompanied by mTOR inhibition. Additionally, this compound inhibited glycolysis, resulting in reduced proliferation of SK-OV-3 cells. Compound 3K treatment suppressed tumor progression in an in vivo xenograft model. Our findings suggest that the inhibition of PKM2 by compound 3K affected the Warburg effect and induced autophagic cell death. Therefore, use of specific PKM2 inhibitors to block the glycolytic pathway and target cancer cell metabolism represents a promising therapeutic approach for treating PKM2-overexpressing ovarian cancer.

The Mechanism of Asparagine Endopeptidase in the Progression of Malignant Tumors: A Review.

Asparagine endopeptidase (AEP), also called legumain, is currently the only known cysteine protease that specifically cleaves peptide bonds in asparaginyl residue in the mammalian genome. Since 2003, AEP has been reported to be widely expressed in a variety of carcinomas and is considered a potential therapeutic target. In the following years, researchers intensively investigated the substrates of AEP and the mechanism of AEP in partial tumors. With the identification of substrate proteins such as P53, integrin αvß3, MMP-2, and MMP-9, the biochemical mechanism of AEP in carcinomas is also more precise. This review will clarify the probable mechanisms of AEP in the progression of breast carcinoma, glioblastoma, gastric carcinoma, and epithelial ovarian carcinoma. This review will also discuss the feasibility of targeted therapy with AEP inhibitor (AEPI) in these carcinomas.

Procaspase-Activating Compound-1 Synergizes with TRAIL to Induce Apoptosis in Established Granulosa Cell Tumor Cell Line (KGN) and Explanted Patient Granulosa Cell Tumor Cells In Vitro.

Granulosa cell tumors (GCT) constitute only ~5% of ovarian neoplasms yet have significant consequences, as up to 80% of women with recurrent GCT will die of the disease. This study investigated the effectiveness of procaspase-activating compound 1 (PAC-1), an activator of procaspase-3, in treating adult GCT (AGCT) in combination with selected apoptosis-inducing agents. Sensitivity of the AGCT cell line KGN to these drugs, alone or in combination with PAC-1, was tested using a viability assay. Our results show a wide range in cytotoxic activity among the agents tested. Synergy with PAC-1 was most pronounced, both empirically and by mathematical modelling, when combined with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). This combination showed rapid kinetics of apoptosis induction as determined by caspase-3 activity, and strongly synergistic killing of both KGN as well as patient samples of primary and recurrent AGCT. We have demonstrated that the novel combination of two pro-apoptotic agents, TRAIL and PAC-1, significantly amplified the induction of apoptosis in AGCT cells, warranting further investigation of this combination as a potential therapy for AGCT.

Estrogen disorders: Interpreting the abnormal regulation of aromatase in granulosa cells (Review).

Ovarian granulosa cells (GCs) are the most important source of estrogen. Therefore, aromatase (estrogen synthase), which is the key enzyme in estrogen synthesis, is not only an important factor of ovarian development, but also the key to estrogen secretion by GCs. Disorders of the ovarian estrogen secretion are more likely to induce female estrogen­dependent diseases and fertility issues, such as ovarian cancer and polycystic ovary syndrome. Hence, aromatase is an important drug target; treatment with its inhibitors in estrogen­dependent diseases has attracted increasing attention. The present review article focuses on the regulation and mechanism of the aromatase activity in the GCs, as well as the specific regulation of aromatase promoters. In GCs, follicle­stimulating hormone (FSH) is dependent on the cyclic adenosine monophosphate (cAMP) pathway to regulate the aromatase activity, and the regulation of this enzyme is related to the activation of signaling pathways, such as phosphatidylinositol 3­kinase (PI3K) and extracellular signal­regulated kinase (ERK). In addition, endocrine­disrupting substance and other related factors affect the expression of aromatase, which eventually create an imbalance in the estrogen secretion by the target tissues. The present review highlights these useful factors as potential inhibitors for target therapy.

Systematic inhibitor selectivity between PARP1 and PARP2 enzymes: Molecular implications for ovarian cancer personalized therapy.

Human poly(ADP-ribose) polymerases (PARPs) are a class of nuclear enzymes involved in the pathogenesis of diverse gynecologic tumors. The PARP1 and PARP2 are the two most documented members in PARP family, which have been approved as the druggable targets of ovarian and cervical cancers. Selective targeting of the two enzymes with small-molecule inhibitors is a great challenge due to the high conservation in catalytic domain and active site. Here, we investigate the systematic selectivity profile of sophisticated PARP inhibitors between the two enzymes. Computational methods are used to model/optimize the complex structures of inhibitor ligands with PARP1/2 catalytic domains and then to estimate the theoretical Fenzymatic assays exhibit a good consistence with theoretical selectivity over six tested inhibitor samples (rc2  = 0.857). It is revealed that the inhibitor selectivity is conferred from the exquisite difference in the residue composition and structural architecture of both the local activity sites and the whole catalytic domains of the two enzymes. In particular, the TMZ50 and ME0328 show strong selectivity between PARP1 and PARP2, but only the former has a potent activity on the two enzymes, whereas the latter can only inhibit the enzymes moderately. These compounds can be considered as potential lead molecular entities to develop new specific PARP-selective inhibitor drugs for personalized therapy combating gynecologic cancers.