Beside P53 and PTEN: Identification of molecular alterations of the RAS/MAPK and PI3K/AKT signaling pathways in high-grade serous ovarian carcinomas to determine potential novel therapeutic targets

PTEN Deficiency in Tubo-Ovarian High-Grade Serous Carcinoma is Associated with Poor Progression-Free Survival and is Mutually Exclusive with CCNE1 Amplification

As a critical tumor suppressor, PTEN has gained much attention in cancer research. Emerging evidence suggests an association between PTEN status and clinical outcome in certain tumors, and may be predictive of response to several therapies. However, the significance of PTEN deficiency in tubo-ovarian high-grade serous carcinomas (HGSCs) is still poorly understood. We evaluated PTEN expression in HGSCs and determined its clinical relevance. A cohort of 76 HGSC specimens was profiled using tissue microarray. Immunohistochemistry (IHC) of PTEN, ER, PR, AR, CD8, FOXP3, and PD-L1 was performed. Targeted gene panel testing by massively parallel sequencing was performed in 51 cases. PTEN deficiency (complete or subclonal loss) detected by IHC was identified in 13 of the 62 HGSCs (21%) and was significantly correlated with reduced expression of ER and worse first progression-free survival (P < .05) but not with PD-L1 expression, the density of intratumoral T lymphocytes, or overall survival. In our cohort, tumor progression within 1 year of PARP inhibitor therapy was found more frequently in PTEN-deficient cases than in PTEN-intact cases (100% vs 52%). Molecular profiling showed that intragenic mutation or deletion was not the predominant mechanism for PTEN inactivation in HGSCs. In addition, CCNE1 amplification was found to be mutually exclusive with PTEN deficiency at both protein and DNA levels. An analysis of the genomic data from 1702 HGSC samples deposited with The Cancer Genome Atlas database obtained from cBioPortal confirmed the low rate of detection of PTEN gene alterations and the mutually exclusive nature of PTEN loss and CCNE1 amplification in HGSCs. These findings indicate that PTEN deficiency defines a distinct clinically significant subgroup of HGSCs with a tendency for ER negativity, wild-type CCNE1 status, inferior clinical outcomes, and potential drug resistance. These tumors may benefit from PI3K pathway inhibitors in combination with other ovarian cancer regimens, which deserves further investigation.

The Challenges and Prospects of p53-Based Therapies in Ovarian Cancer

It has been well established that mutations in the tumor suppressor gene, p53, occur readily in a vast majority of cancer tumors, including ovarian cancer. Typically diagnosed in stages three or four, ovarian cancer is the fifth leading cause of death in women, despite accounting for only 2.5% of all female malignancies. The overall 5-year survival rate for ovarian cancer is around 47%; however, this drops to an abysmal 29% for the most common type of ovarian cancer, high-grade serous ovarian carcinoma (HGSOC). HGSOC has upwards of 96% of cases expressing mutations in p53. Therefore, wild-type (WT) p53 and p53-based therapies have been explored as treatment options via a plethora of drug delivery vehicles including nanoparticles, viruses, polymers, and liposomes. However, previous p53 therapeutics have faced many challenges, which have resulted in their limited translational success to date. This review highlights a selection of these historical p53-targeted therapeutics for ovarian cancer, why they failed, and what the future could hold for a new generation of this class of therapies.

The role of distinct BRD4 isoforms and their contribution to high-grade serous ovarian carcinoma pathogenesis

High-grade serous ovarian carcinoma (HGSOC) is the most aggressive type of ovarian cancer, often diagnosed at advanced stages. Molecularly, HGSOC shows high degree of genomic instability associated with large number of genetic alterations. BRD4 is the 4th most amplified gene in HGSOC, which correlates with poor patients' prognosis. BRD4 is constitutively expressed and generates two proteins, BRD4 long (BRD4-L) and BRD4 short (BRD4-S). Both isoforms contain bromodomains that bind to lysine-acetylated histones. Amongst other functions, BRD4 participates in chromatin organization, acetylation of histones, transcriptional control and DNA damage repair. In cancer patients with amplified BRD4, the increased activity of BRD4 is associated with higher expression of oncogenes, such as MYC, NOTCH3 and NRG1. BRD4-driven oncogenes promote increased tumor cells proliferation, genetic instability, epithelial-mesenchymal transition, metastasis and chemoresistance. Ablation of BRD4 activity can be successfully achieved with bromodomain inhibitors (BETi) and degraders, and it has been applied in pre-clinical and clinical settings. Inhibition of BRD4 function has an effective anti-cancer effect, reducing tumor growth whether ablated by single agents or in combination with other drugs. When combined with standard chemotherapy, BETi are capable of sensitizing highly resistant ovarian cancer cell lines to platinum drugs. Despite the evidence that BRD4 amplification in ovarian cancer contributes to poor patient prognosis, little is known about the specific mechanisms by which BRD4 drives tumor progression. In addition, newly emerging data revealed that BRD4 isoforms exhibit contradicting functions in cancer. Therefore, it is paramount to expand studies elucidating distinct roles of BRD4-L and BRD4-S in HGSOC, which has important implications on development of therapeutic approaches targeting BRD4.

Anti-Tumor Xanthones from Garcinia nujiangensis Suppress Proliferation, and Induce Apoptosis via PARP, PI3K/AKT/mTOR, and MAPK/ERK Signaling Pathways in Human Ovarian Cancers Cells

BACKGROUND

Ovarian cancer (OC) is a serious public health concern in the world. It is important to develop novel drugs to inhibit OC.

PURPOSE

This study investigated the isolation, elucidation, efficiency, molecular docking, and pharmaceutical mechanisms of xanthones isolated from Garcinia nujiangensis.

METHODS

Xanthones were isolated, and purified by different chromatography, including silica gel, reversed-phase silica gel (ODS-C18), and semipreparative HPLC, then identified by analysis of their spectral data. Three xanthones were estimated for their efficiency on the human OC cells HEY and ES-2. 2 was found to be the most potent cytotoxic xanthones of those tested. Further, its mechanisms of action were explored by molecular docking, cell apoptosis, and Western blotting analysis.

RESULTS

Bioassay-guided fractionation of the fruits of Garcinia nujiangensis led to the separation of a new xanthone named nujiangexanthone G (1) and two known xanthones. Among these, isojacareubin (2) exhibited the most potent cytotoxic compound against the HEY and ES-2 cell lines. The analysis of Western blot suggested that 2 inhibited OC via regulating the PARP, PI3K/AKT/mTOR, and ERK/MAPK signal pathways in the HEY cell lines.

CONCLUSION

In conclusion, isojacareubin (2) might be a potential drug for the treatment of OC.

Human umbilical cord-derived mesenchymal stem cells ameliorate insulin resistance via PTEN-mediated crosstalk between the PI3K/Akt and Erk/MAPKs signaling pathways in the skeletal muscles of db/db mice

Background

Globally, 1 in 11 adults have diabetes mellitus, and 90% of the cases are type 2 diabetes mellitus. Insulin resistance is a central defect in type 2 diabetes mellitus, and although multiple drugs have been developed to ameliorate insulin resistance, the limitations and accompanying side effects cannot be ignored. Thus, more effective methods are required to improve insulin resistance.

Methods

In the current study, db/m and db/db mice were injected with human umbilical cord-derived mesenchymal stem cells (HUC-MSCs) via tail vein injection, intraperitoneal injection, and skeletal muscle injection. Body weight, fasting blood glucose, and the survival rates were monitored. Furthermore, the anti-insulin resistance effects and potential mechanisms of transplanted HUC-MSCs were investigated in db/db mice in vivo.

Results

The results showed that HUC-MSC transplantation by skeletal muscle injection was safer compared with tail vein injection and intraperitoneal injection, and the survival rate reached 100% in the skeletal muscle injection transplanted mice. HUC-MSCs can stabilize localization and differentiation in skeletal muscle tissue and significantly ameliorate insulin resistance. Potential regulatory mechanisms are associated with downregulation of inflammation, regulating the balance between PI3K/Akt and ERK/MAPK signaling pathway via PTEN, but was not associated with the IGF-1/IGF-1R signaling pathway.

Conclusions

These results suggest HUC-MSC transplantation may be a novel therapeutic direction to prevent insulin resistance and increase insulin sensitivity, and skeletal muscle injection was the safest and most effective way.

Morphological and molecular heterogeneity of epithelial ovarian cancer: Therapeutic implications

Ovarian epithelial cancer (OEC) is the most lethal gynecologic malignancy. Despite current chemotherapeutic and surgical options, this high lethality can be attributed to multiple factors, including late-stage presentation. In order to optimize OEC treatment, it is important to highlight that it is composed of five main subtypes: high-grade serous ovarian carcinoma (HGSOC), low-grade serous ovarian carcinoma (LGSOC), endometrioid ovarian carcinoma (EOC), ovarian clear cell carcinoma (CCOC), and mucinous ovarian carcinoma (MOC). These subtypes differ in their precursor lesions, as well as in epidemiological, morphological, molecular and clinical features. OEC is one of the tumours in which most pathogenic germline mutations have been identified. Accordingly, up to 20% OC show alterations in BRCA1/2 genes, and also, although with a lower frequency, in other low penetrance genes associated with homologous recombination deficiency (HRD), mismatch repair genes (Lynch syndrome) and TP53. The most important prognostic factor is the 2014 FIGO staging, while older age is also associated with worse survival. HGSOC in all stages and CCC and MOC in advanced stages have the worse prognosis among histological types. Molecular markers have emerged as prognostic factors, particularly mutations in BRCA1/2, which are associated with a better outcome. Regarding treatment, whereas a proportion of HGSOC is sensible to platinum-based treatment and PARP inhibitors due to HRD, the rest of the histological types are relatively chemoresistant. New treatments based in specific molecular alterations are being tested in different histological types. In addition, immunotherapy could be an option, especially for EOC carrying mismatch repair deficiency or POLE mutations.

•

The five different histological types have different precursor lesions and epidemiological, morphological, genetic, epigenetic and clinical features.

•

Histological type is an important prognostic factor.

•

Drugs targeting homologous recombination deficiency have been approved for treatment.

•

The use of immunotherapy is limited due to lack of predictive biomarkers

Segmental Ipsilateral Odontognathic Dysplasia (Mandibular Involvement in Segmental Odontomaxillary Dysplasia?) and Identification of PIK3CA Somatic Variant in Lesional Mandibular Gingival Tissue

Segmental odontomaxillary dysplasia (SOD) is a developmental condition of the middle and posterior maxilla featuring dysplastic bone overgrowth, dental abnormalities and, occasionally, various homolateral cutaneous manifestations. Herein, we describe an individual with maxillary abnormality akin to SOD and associated ipsilateral segmental odontomandibular dysplasia. Also, the result of the evaluation of lesional mandibular gingival tissue for overgrowth-related gene variants is reported. An 8-year-old girl presented clinically with congenital maxillary and mandibular alveolar soft tissue enlargement in the area of the premolars. A panoramic radiograph revealed abnormal trabeculation essentially similar to SOD in the maxilla and mandible with congenitally missing maxillary and mandibular first and second premolars and mandibular canines. Diagnostic mandibular bone biopsy was performed and lesional mandibular gingival hyperplastic tissue was obtained for variant analysis of somatic overgrowth genes PIK3CA, AKT1, AKT3, GNAQ, GNA11, MTOR, PIK3R2. Cone beam computerized tomography (CBCT) disclosed osseous abnormalities on the left side of the maxilla and mandible and very mild osseous expansion in the mandible. Histologically, abnormal bone exhibiting prominent reversal lines was present and associated with fibrocollagenous tissue. Genomic DNA analysis disclosed PIK3CAc.1571G>A; pArg524Lys which was seen at a low mosaic level in the blood, indicating a post-zygotic change. Although this case may be a unique disorder, by sharing features with SOD, one can suggest the possibility of mandibular involvement in SOD. The presence of a PIK3CA variant may support the hypothesis that these segmental disorders could be part of the PIK3CA-related overgrowth spectrum.

Origins based clinical and molecular complexities of epithelial ovarian cancer

Ovarian cancer is the most lethal of all common gynaecological malignancies in women worldwide. Ovarian cancer comprises of >15 distinct tumor types and subtypes characterized by histopathological features, environmental and genetic risk factors, precursor lesions and molecular events during oncogenesis. Recent studies on gene signature profiling of different subtypes of ovarian cancer have revealed significant genetic heterogeneity between and within each ovarian cancer histological subtype. Thus, an immense interest have shown towards a more personalized medicine for understanding the clinical and molecular complexities of four major types of epithelial ovarian cancer (serous, endometrioid, clear cell, and mucinous). As such, further in depth studies are needed for identification of molecular signalling network complexities associated with effective prognostication and targeted therapies to prevent or treat metastasis. Therefore, understanding the metastatic potential of primary ovarian cancer and therapeutic interventions against lethal ovarian cancer for the development of personalized therapies is very much indispensable. Consequently, in this review we have updated the key dysregulated genes of four major subtypes of epithelial carcinomas. We have also highlighted the recent advances and current challenges in unravelling the complexities of the origin of tumor as well as genetic heterogeneity of ovarian cancer.

WT1, p53 and p16 expression in the diagnosis of low- and high-grade serous ovarian carcinomas and their relation to prognosis

Objective

To evaluate the diagnostic and prognostic value of the immunohistochemical expression of WT1, p53 and p16 in low- (LGSOCs) and high-grade serous ovarian carcinomas (HGSOCs).

Results

HGSOC had a significantly higher proportion of advanced stage disease, higher CA125 levels, higher proportion of post-surgery residual disease and higher recurrence or disease progression. WT1 was expressed in 71.4% of LGSOCs and in 57.1% of HGSOCs (p = 0.32). Focal and/or complete absence of p53 expression with negative p16 expression was found in 90.5% of LGSOCs, in contrast to the 88.1% of HGSOCs with diffuse or complete absence of p53 expression with positive p16 expression (<0.001). The IHC p53/p16 index and the morphological classification were closely matched (k = 0.68). In the univariate analysis, FIGO stage, post-surgery residual disease and histological grade were significantly associated with progression-free survival (PFS) and overall survival (OS). The IHC p53/p16 index was associated only with PFS. WT1 was not associated with PFS or OS. According to the multivariate analysis, advanced FIGO stage and presence of post-surgery residual disease remained independent prognostic factors for worst PFS, however these features had only a trend association with OS.

Methods

21 LGSOC and 85 HGSOC stage I-IV cases were included. The morphological classification was assessed according to the World Health Organization (WHO) criteria. Immunohistochemistry (IHC) was performed in tissue microarray slides. IHC p53/p16 index was compared with the morphological classification.

Conclusions

The IHC p53/p16 index was a good marker for the differentiation of LGSOC and HGSOC, but the morphologic classification showed a better association with survival. FIGO stage and post-surgery residual disease remained the only independent prognostic factors for survival.

WT1, p53 and p16 expression in the diagnosis of low- and high-grade serous ovarian carcinomas and their relation to prognosis

Objective

To evaluate the diagnostic and prognostic value of the immunohistochemical expression of WT1, p53 and p16 in low- (LGSOCs) and high-grade serous ovarian carcinomas (HGSOCs).

Results

HGSOC had a significantly higher proportion of advanced stage disease, higher CA125 levels, higher proportion of post-surgery residual disease and higher recurrence or disease progression. WT1 was expressed in 71.4% of LGSOCs and in 57.1% of HGSOCs (p = 0.32). Focal and/or complete absence of p53 expression with negative p16 expression was found in 90.5% of LGSOCs, in contrast to the 88.1% of HGSOCs with diffuse or complete absence of p53 expression with positive p16 expression (<0.001). The IHC p53/p16 index and the morphological classification were closely matched (k = 0.68). In the univariate analysis, FIGO stage, post-surgery residual disease and histological grade were significantly associated with progression-free survival (PFS) and overall survival (OS). The IHC p53/p16 index was associated only with PFS. WT1 was not associated with PFS or OS. According to the multivariate analysis, advanced FIGO stage and presence of post-surgery residual disease remained independent prognostic factors for worst PFS, however these features had only a trend association with OS.

Methods

21 LGSOC and 85 HGSOC stage I–IV cases were included. The morphological classification was assessed according to the World Health Organization (WHO) criteria. Immunohistochemistry (IHC) was performed in tissue microarray slides. IHC p53/p16 index was compared with the morphological classification.

Conclusions

The IHC p53/p16 index was a good marker for the differentiation of LGSOC and HGSOC, but the morphologic classification showed a better association with survival. FIGO stage and post-surgery residual disease remained the only independent prognostic factors for survival.

Sequential molecular changes and dynamic oxidative stress in high-grade serous ovarian carcinogenesis

The mechanism of high-grade serous ovarian cancer (HGSC) development remains elusive. This review outlines recent advances in the understanding of sequential molecular changes associated with the development of HGSC, as well as describes oxidative stress-induced genomic instability and carcinogenesis. This article reviews the English language literature between 2005 and 2017. Clinicopathological features analysis provides a sequential progression of fallopian tubal epithelium to precursor lesions to type 2 HGSC. HGSC may develop over a long time after incessant ovulation and repeated retrograde menstruation via stepwise accumulation of genetic alterations, including PAX2, ALDH1A1, STMN1, EZH2 and CCNE1, which confer positive selection of cells with growth advantages through acquiring driver mutations such as BRCA1/2, p53 or PTEN/PIK3CA. Haemoglobin and iron-induced oxidative stress leads to the emergence of genetic alterations in fallopian tubal epithelium via increased DNA damage and impaired DNA repair. Serous tubal intraepithelial carcinoma (STIC), the likely precursor of HGSC, may be susceptible to DNA double-strand breaks, exhibit DNA replication stress and increase genomic instability. The induction of genomic instability is considered to be a driving mechanism of reactive oxygen species (ROS)-induced carcinogenesis. HGSC exemplifies the view of stepwise cancer development. We describe how genetic alterations emerge during HGSC carcinogenesis related to oxidative stress.

Effects of Endocrine-Disrupting Chemicals and Epigenetic Modifications in Ovarian Cancer: A Review

Ovarian cancer (OC) is a relatively fatal female reproductive malignancy. Since the underlying causes are uncertain, it brings us to believe that both genetic and external factors contribute toward development of this lethal disorder. Exposure to endocrine-disrupting chemicals (EDCs) in the form of occupational usage of pesticides, fungicides, herbicides, plasticizers, cosmetics, and so on is potentially carcinogenic and their ability to cause epigenetic modifications has led us to hypothesize that they may play a catalytic role in OC progression. In response to synthetic chemicals, animal models have demonstrated disturbances in the development of ovaries and steroid hormonal levels but in humans, more research is required. The present review is an attempt to address the impact of EDCs on the hormonal system and gene methylation levels that may lead to malfunctioning of the ovaries which may consequently develop in the form of cancer. It can be concluded that endocrine disruptors do have a potential carcinogenicity and their high proportions in human body may cause epigenetic modifications, prompting ovarian surface epithelium to grow in an abnormal manner.

MiR-200a and miR-200b target PTEN to regulate the endometrial cancer cell growth in vitro

OBJECTIVE

To study whether miR-200a and miR-200b target PTEN gene expression to regulate the endometrial cancer cell growth in vitro.

METHODS

Endometrial cancer cells ECC-1 were cultured and transfected with the miR-200a and miR-200b mimics and inhibitors as well as the negative control mimics and inhibitors, and then the cell proliferation activity as well as the expression of PTEN and downstream genes in cells was determined; after transfection of miR-200a and miR-200b mimics as well as PTEN-3'UTR luciferase report gene plasmids, the fluorescence activity of luciferase reporter gene was determined.

RESULTS

12 h, 24 h and 48 h after transfection, the cell proliferation activity of miR-200a mimics group and miR-200b mimics group were significantly higher than those of NC mimics group while the cell proliferation activity of miR-200a inhibitor group and miR-200b inhibitor group were significantly lower than those of NC inhibitor group; 48 h after transfection, PTEN expression in cells and PTEN-3'UTR luciferase reporter gene fluorescence activity of miR-200a mimics group and miR-200b mimics group were significantly lower than those of NC mimics group while p-PI3K and p-Akt expression were significantly higher than those of NC mimics group; PTEN expression in cells and PTEN-3'UTR luciferase reporter gene fluorescence activity of miR-200a inhibitor group and miR-200b inhibitor group were significantly higher than those of NC inhibitor group while p-PI3K and p-Akt expression were significantly lower than those of NC inhibitor group.

CONCLUSION

miR-200a and miR-200b can promote the endometrial cancer cell growth in vitro by targeted inhibition of PTEN gene expression.