High frequency of PIK3R1 and PIK3R2 mutations in endometrial cancer elucidates a novel mechanism for regulation of PTEN protein stability

Neomorphic mutations create therapeutic challenges in cancer

Oncogenesis is a pathologic process driven by genomic aberrations, including changes in nucleotide sequences. The majority of these mutational events fall into two broad categories: inactivation of tumor suppressor genes (hypomorph, antimorph or amorph) or activation of oncogenes (hypermorph). The recent surge in genome sequence data and functional genomics research has ushered in the discovery of aberrations in a third category: gain-of-novel-function mutation (neomorph). These neomorphic mutations, which can be found in both tumor suppressor genes and oncogenes, produce proteins with entirely different functions from their respective wild-type (WT) proteins and the other morphs. The unanticipated phenotypic outcomes elicited by neomorphic mutations imply that tumors with the neomorphic mutations may not respond to therapies designed to target the WT protein. Therefore, understanding the functional activities of each genomic aberration to be targeted is crucial in devising effective treatment strategies that will benefit specific cancer patients.

The emerging role of long non-coding RNAs in endometrial cancer

The human genome is pervasively transcribed and approximately 98% of the genome is non-coding. Long non-coding RNAs (lncRNAs) are a heterogeneous group of RNA transcripts that are >200 nucleotides in length with minimal to no protein-coding potential. Similar to proteins, lncRNAs have important biological functions in both normal cells and disease states including many types of cancer. This review summarizes recent advances in our understanding of lncRNAs in cancer biology and highlights the potential for lncRNA as diagnostic biomarkers and therapeutics. Herein we focus on the poorly understood role of lncRNAs in endometrial cancer, the most common gynecologic malignancy in the developed world.

A multicenter, single-arm, open-label, phase 2 study of apitolisib (GDC-0980) for the treatment of recurrent or persistent endometrial carcinoma (MAGGIE study)

BACKGROUND

The current single-arm, open-label trial was designed to evaluate the activity of apitolisib (GDC-0980), a dual phosphoinositide 3-kinase/mammalian target of rapamycin (PI3K/mTOR) inhibitor, in patients with advanced endometrial cancer (EC).

METHODS

Patients with recurrent or persistent EC who were treated with 1 to 2 prior lines of chemotherapy but no prior PI3K/mTOR inhibitor received oral apitolisib at a dose of 40 mg daily during 28-day cycles until disease progression or intolerable toxicity occurred. Patients with type I/II diabetes who required insulin were excluded. The primary endpoints were progression-free survival (PFS) at 6 months and objective response rate.

RESULTS

A total of 56 women were enrolled, including 13 (23%) with well-controlled diabetes. Reasons for discontinuation were disease progression (24 patients; 43%), adverse events (13 patients; 23%), and withdrawal by subject (12 patients; 21%). Grade 3/4 apitolisib-related adverse events were hyperglycemia (46%), rash (30%), colitis (5%), and pneumonitis (4%) (toxicities were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events [version 4.0]). The PFS rate at 6 months was 20% (Kaplan-Meier estimate; 95% confidence interval [95% CI], 7%-33%). The objective response rate was 6% (confirmed). The median PFS was 3.5 months (95% CI, 2.7-3.7 months) and the median overall survival was 15.7 months (95% CI, 9.2-17.0 months). Nineteen patients discontinued the study before the first tumor assessment. Dose reductions were required for 4 diabetic (31%) and 18 nondiabetic (42%) patients. Comprehensive molecular profiling of 46 evaluable archival tumor samples demonstrated that 57% of patients had at least 1 alteration in phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), phosphatase and tensin homolog (PTEN), or AKT1. All 3 patients with a confirmed response had at least 1 alteration in a PI3K pathway gene.

CONCLUSIONS

The antitumor activity noted with the use of a dose of 40 mg of apitolisib daily was limited by tolerability, especially in diabetic patients. Patients with PI3K pathway mutations may have derived enhanced benefit from apitolisib. Cancer 2016;122:3519-28. © 2016 American Cancer Society.

LAT1 is a putative therapeutic target in endometrioid endometrial carcinoma

l-type amino acid transporters (LAT1-4) are expressed in various cancer types and are involved in the uptake of essential amino acids such as leucine. Here we investigated the expression of LAT1-4 in endometrial adenocarcinoma and evaluated the contribution of LATs to endometrial cancer cell growth. Analysis of human gene expression data showed that all four LAT family members are expressed in endometrial adenocarcinomas. LAT1 was the most highly expressed, and showed a significant increase in both serous and endometrioid subtypes compared to normal endometrium. Endometrioid patients with the highest LAT1 levels exhibited the lowest disease-free survival. The pan-LAT inhibitor BCH led to a significant decrease in cell growth and spheroid area in four endometrial cancer cell lines tested in vitro. Knockdown of LAT1 by shRNA inhibited cell growth in HEC1A and Ishikawa cells, as well as inhibiting spheroid area in HEC1A cells. These data show that LAT1 plays an important role in regulating the uptake of essential amino acids such as leucine into endometrial cancer cells. Increased ability of BCH compared to LAT1 shRNA at inhibiting Ishikawa spheroid area suggests that other LAT family members may also contribute to cell growth. LAT1 inhibition may offer an effective therapeutic strategy in endometrial cancer patients whose tumours exhibit high LAT1 expression.

Use of comprehensive genomic profiling to direct point-of-care management of patients with gynecologic cancers

OBJECTIVE

To determine the feasibility and clinical utility of using comprehensive genomic profiling (CGP) in the course of clinical care to identify clinically relevant tumor genomic alterations for patients with either rare or refractory gynecologic cancers to facilitate point-of-care management. Use of an expert, multidisciplinary, institutional molecular tumor board (MTB) assessment is discussed regarding input on putative targeted options for individualized therapy.

METHODS

A prospective clinical trial is ongoing. We report on the initial 69 patients with gynecologic cancers that were either rare or refractory to standard therapy. CGP was performed by Foundation Medicine, Inc. Genomic alterations were reviewed by members of an MTB. Consensus recommendations on genomically targeted, FDA-approved, on- and off-label therapies and clinical trials were sent to the treating physician, and decisions and outcomes were assessed.

RESULTS

Study outcomes were available for 64 patients. The mean number of genes altered per tumor was 4.97 (median=4; range, 1-26), and the average turnaround time from testing laboratory report to generation of formal recommendations was approximately three weeks. Evaluation of genomic and clinical data by the MTB led to generation of targeted treatment options in all 64 patients, and the percentage of patients for whom one or more of these recommendations were implemented by the treating physician was 39%. Sixty-four percent of the patients receiving targeted therapy based on a CGP result experienced radiologic response or showed evidence of clinical benefit or stable disease.

CONCLUSION

These data suggest that an institutional MTB is a feasible venue for reviewing tumor genomic profiling results and generating clinical recommendations. These data also support the need for further studies and guidelines on clinical decision making with greater availability of broad genomically based diagnostics.

Geraniol Inhibits Endometrial Carcinoma via Downregulating Oncogenes and Upregulating Tumour Suppressor Genes

Endometrial carcinoma is the fourth most abundant cancer worldwide in women. Female Wistar rats were segregated into five groups: group I-control, group II-MNNG (N-methyl-N'-nitro-N-nitrosoguanidine-150 mg/kg) administered through intravaginal detention of cotton absorbent, group III-geraniol (GOH) only, group IV-GOH-pretreated (7 days before the start of MNNG administration); and group V-Co-administration of geraniol with MNNG. In this study, reverse transcriptase- PCR of K-ras, MAPK, PI3K, Wnt/β-catenin genes, TGF-β and expressions of PCNA, PTEN, progesterone receptor and E-cadherin by Western blotting were performed from endometrial cancer tissue and control tissues. The mRNA expressions of K-ras, MAPK, PI3K, Wnt/β-catenin and TGF-β were amplified in MNNG induced group. Oral administration of GOH (both pre and co-administration) reversed the mRNA expression towards normal. The reversibility is more predominant in pretreatment groups (p < 0.05). The expression of PCNA was upregulated and downregulation of PTEN, progesterone receptor and E-cadherin was noticed in MNNG induced rats. Pre and co-administration of GOH significantly reversed the expression pattern of proteins. GOH treatment is more effective in pretreatment groups (p < 0.05). These results provide powerful evidences that GOH could influence modulation of MAPK pathways and Wnt signalling pathways in the prevention of endometrial carcinoma in rats.

Will targeting PI3K/Akt/mTOR signaling work in hematopoietic malignancies?

The constitutive activation of phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway has been demonstrated to be critical in clinical cancer patients as well as in laboratory cancer models including hematological malignancies. Great efforts have been made to develop inhibitors targeting this pathway in hematological malignancies but so far the efficacies of these inhibitors were not as good as expected. By analyzing existing literatures and datasets available, we found that mutations of genes in the pathway only constitute a very small subset of hematological malignancies. Deep understanding of the function of gene, the pathway and/or its regulators, and the cellular response to inhibitors, may help us design better drugs targeting the hematological malignancies.

Clinical translation for endometrial cancer stem cells hypothesis

Endometrial cancer is the most frequent gynecological malignancy in developed world. Cancer stem cells (CSC) are recognized as a small proportion of cells among the tumor cell population that are capable of self-renewal, aberrant differentiation, and escape homeostasis. This review aims to systematize the existing evidence of CSC of endometrial cancer and its clinical translation. In endometrial cancer, the cancer stem cell hypothesis has been studied in vitro using the isolation of colony forming units, side population with dye efflux capacity, and tumorospheres. The stem cell markers for endometrial cancer do not have uniform characteristics, albeit CD133 and aldehyde dehydrogenase (ALDH) were being associated with CSC phenotype. The application of endometrial CSC on xenograft models proves the tumorigenic capacity of this small group of cells. The metastatic process has been explained due to epithelial-mesenchymal transition (EMT) in which CSC seems to have a critical role. The chemoresistance is characteristic of CSC that in endometrial cancer has been shown in CSC phenotype and associated with CSC markers. The most ambitious potential for CSC is the development of targeted therapies. Its application on endometrial cancer is still poor, being a future perspective for research.

RNASeq analysis reveals biological processes governing the clinical behaviour of endometrioid and serous endometrial cancers

BACKGROUND

Endometrial carcinoma comprises a group of tumours with distinct histologic and molecular features and clinical behaviour. Here, we sought to define the biological processes that govern the clinical behaviour of endometrial cancers.

METHODS

Sixteen prototype genes representative of different biological processes that would likely play a role in endometrial and other hormone-driven cancers were defined. RNA-sequencing gene expression data from 323 endometrial cancers from The Cancer Genome Atlas (TCGA) were used to determine the transcription module of each prototype gene. The expression of prototype genes and modules and their association with outcome was assessed in univariate and multivariate survival analyses. The association of MSH6 expression with outcome was validated in an independent cohort of 243 primary endometrial cancers using immunohistochemistry.

RESULTS

We observed that the clinical behaviour of endometrial cancers as a group was associated with hormone receptor signalling, PI3K pathway signalling and DNA mismatch repair processes. When analysed separately, in endometrioid carcinomas, hormone receptor, PI3K and DNA mismatch repair modules were significantly associated with outcome in univariate analysis, whereas the clinical behaviour of serous cancers was likely governed by apoptosis and Wnt signalling. Multivariate survival analysis revealed that MSH6 gene expression was associated with outcome of endometrial cancer patients independently from traditional prognostic clinicopathologic parameters, which was confirmed in an independent cohort at the protein level.

CONCLUSION

Endometrioid and serous endometrial cancers are underpinned by distinct molecular pathways. MSH6 expression levels may be associated with outcome in endometrial cancers as a group.

Tumor genotype and immune microenvironment in POLE-ultramutated and MSI-hypermutated Endometrial Cancers: New candidates for checkpoint blockade immunotherapy?

Endometrial Cancer (EC) is still a challenge for gynecological oncologists because the treatment of the advanced disease remains an unmet need for patients. The Cancer Genome Atlas Research Network (TCGA) recently provided a comprehensive genomic and transcriptomic analysis of EC, offering a new classification of the disease, based on genetic features, which defines four subgroups of cancer rather than the two traditionally recognized. In the molecular classification two types of EC, the polymerase epsilon (POLE)-ultramutated and the microsatellite instability (MSI)-hypermutated, seem to present an enhanced immune microenvironment and a high mutation burden. The blockade of the immune checkpoints is an innovative approach that has largely demonstrated to be effective in solid malignancies, such as lung, renal and melanoma; it acts by reducing the cancer-induced immune-suppression through inhibition of the PD-1/PD-L1 (Programmed Death and PD-Ligand) axis. All available evidence supporting an over-expression of the PD-1/PD-L1 pathway in EC has been reviewed. In particular in the POLE and MSI ECs an up-regulation of this pathway was found, aiming to suggest a rationale for testing the PD-1/PD-L1 immunotherapy in these cancer subgroups.

A Multi-Step miRNA-mRNA Regulatory Network Construction Approach Identifies Gene Signatures Associated with Endometrioid Endometrial Carcinoma

We aimed to identify endometrioid endometrial carcinoma (EEC)-related gene signatures using a multi-step miRNA-mRNA regulatory network construction approach. Pathway analysis showed that 61 genes were enriched on many carcinoma-related pathways. Among the 14 highest scoring gene signatures, six genes had been previously shown to be endometrial carcinoma. By qRT-PCR and next generation sequencing, we found that a gene signature (CPEB1) was significantly down-regulated in EEC tissues, which may be caused by hsa-miR-183-5p up-regulation. In addition, our literature surveys suggested that CPEB1 may play an important role in EEC pathogenesis by regulating the EMT/p53 pathway. The miRNA-mRNA network is worthy of further investigation with respect to the regulatory mechanisms of miRNAs in EEC. CPEB1 appeared to be a tumor suppressor in EEC. Our results provided valuable guidance for the functional study at the cellular level, as well as the EEC mouse models.

A Common Variant at the 14q32 Endometrial Cancer Risk Locus Activates AKT1 through YY1 Binding

A recent meta-analysis of multiple genome-wide association and follow-up endometrial cancer case-control datasets identified a novel genetic risk locus for this disease at chromosome 14q32.33. To prioritize the functional SNP(s) and target gene(s) at this locus, we employed an in silico fine-mapping approach using genotyped and imputed SNP data for 6,608 endometrial cancer cases and 37,925 controls of European ancestry. Association and functional analyses provide evidence that the best candidate causal SNP is rs2494737. Multiple experimental analyses show that SNP rs2494737 maps to a silencer element located within AKT1, a member of the PI3K/AKT/MTOR intracellular signaling pathway activated in endometrial tumors. The rs2494737 risk A allele creates a YY1 transcription factor-binding site and abrogates the silencer activity in luciferase assays, an effect mimicked by transfection of YY1 siRNA. Our findings suggest YY1 is a positive regulator of AKT1, mediating the stimulatory effects of rs2494737 increasing endometrial cancer risk. Identification of an endometrial cancer risk allele within a member of the PI3K/AKT signaling pathway, more commonly activated in tumors by somatic alterations, raises the possibility that well tolerated inhibitors targeting this pathway could be candidates for evaluation as chemopreventive agents in individuals at high risk of developing endometrial cancer.

YAP/TAZ regulates the insulin signaling via IRS1/2 in endometrial cancer

Insulin resistance (IR) is an important mechanism of pathogenesis of endometrial cancer (EC) and explains the pathogenic mechanism of high risk factors including Obesity BMI (body mass index), Type 2 Diabetes Mellitus, PCOS and so on. Relieving IR or inhibiting the function of insulin could be one of the potential therapeutic strategies for EC, which is a PI3K-driven disease. PI3K/Akt are the central mediators for insulin/IGF1 signaling, however, the involvement of HIPPO pathway co-activators, YAP and TAZ, in insulin resistance remains to be elucidated. In the present study, we analyzed the clinical and biological data of EC patients from TCGA and observed a correlation between insulin resistance and EC. By comparing the expression level of IRS1/2 in obese vs non-obese patients, we found that the most important insulin resistance relative (IRR) genes are the contributing factors to IR. Interestingly, IRS1/2 was correlated positively with YAP/TAZ in EC patients. Knockdown of YAP/TAZ by specific siRNA inhibited the phosphorylation of IRS1 while increased the phosphorylation of IGFR1, the inhibitor of insulin signaling. Treating EC with siYAP/TAZ, YAP inhibitor Verteporfin or metformin alone only partially inhibited the function of insulin and IGF1. However, combination of siYAP/TAZ with metformin could completely inhibit the effects of insulin. Thus, our study demonstrated a novel function of YAP and TAZ in the insulin resistance via IRS1/2 in endometrial cancer. Our study also provided the rationale for the potential therapeutic treatment of EC with the combination of inhibiting YAP/TAZ and metformin.

PI3K as a Potential Therapeutic Target in Thymic Epithelial Tumors

INTRODUCTION

Thymic epithelial tumors (TETs) are rare tumors originating from the epithelium of the thymus with limited therapeutic options beyond surgery. The pathogenesis of TETs is poorly understood, and the scarcity of model systems for these rare tumors makes the study of their biology very challenging.

METHODS

A new cell line (MP57) was established from a thymic carcinoma specimen and characterized using standard biomarker analysis, as well as next-generation sequencing (NGS) and functional assays. Sanger sequencing was used to confirm the mutations identified by NGS.

RESULTS

MP57 possesses all the tested thymic epithelial markers and is deemed a bona fide thymic carcinoma cell line. NGS analysis of MP57 identified a mutation in the gene PIK3R2, which encodes a regulatory subunit of PI3K. Further analysis identified different mutations in multiple PI3K subunit genes in another cell line and several primary thymic carcinoma samples, including two catalytic subunits (PIK3CA and PIK3CG) and another regulatory subunit (PIK3R4). Inhibiting PI3K with GDC-0941 resulted in in vitro antitumor activity in TET cells carrying mutant PI3K subunits.

CONCLUSIONS

Alterations of PI3K due to mutations in its catalytic or regulatory subunits are observed in a subgroup of TETs, in particular, thymic carcinomas. Targeting PI3K may be an effective strategy to treat these tumors.

Prediction of key genes in ovarian cancer treated with decitabine based on network strategy

The objective of the present study was to predict key genes in ovarian cancer before and after treatment with decitabine utilizing a network approach and to reveal the molecular mechanism. Pathogenic networks of ovarian cancer before and after treatment were identified based on known pathogenic genes (seed genes) and differentially expressed genes (DEGs) detected by Significance Analysis of Microarrays (SAM) method. A weight was assigned to each gene in the pathogenic network and then candidate genes were evaluated. Topological properties (degree, betweenness, closeness and stress) of candidate genes were analyzed to investigate more confident pathogenic genes. Pathway enrichment analysis for candidate and seed genes were conducted. Validation of candidate gene expression in ovarian cancer was performed by reverse transcriptase-polymerase chain reaction (RT-PCR) assays. There were 73 nodes and 147 interactions in the pathogenic network before treatment, while 47 nodes and 66 interactions after treatment. A total of 32 candidate genes were identified in the before treatment group of ovarian cancer, of which 16 were rightly candidate genes after treatment and the others were silenced. We obtained 5 key genes (PIK3R2, CCNB1, IL2, IL1B and CDC6) for decitabine treatment that were validated by RT-PCR. In conclusion, we successfully identified 5 key genes (PIK3R2, CCNB1, IL2, IL1B and CDC6) and validated them, which provides insight into the molecular mechanisms of decitabine treatment and may be potential pathogenic biomarkers for the therapy of ovarian cancer.

A dual PI3K/AKT/mTOR signaling inhibitor miR-99a suppresses endometrial carcinoma

Activation of the PI3K/AKT/mTOR signaling pathway, a common mechanism in all subtypes of endometrial cancers (EC), plays an important role in the initiation and progression of many cancers. Inhibitors against various components of this pathway might promise a novel effective approach for targeted therapy for EC in the future. Intriguingly, two major members of this pathway, AKT1 and mTOR, were both reported to be the putative target genes of miR-99a, which were widely reported to function as a tumor suppressor in a variety of cancers. However, the direct role of miR-99a in endometrial cancer progression and the signaling pathways might been involved have never been deciphered. In this paper, we demonstrate that the expression of miR-99a was significantly suppressed in the EC tissues and was negatively correlated with the differentiation of tumors. Furthermore, we find that overexpression of miR-99a in EC cells induced a complex phenotype, namely an inhibition of cell proliferation, block of G1/S phase transition, induction of cell apoptosis, suppression of cell invasion, and inhibition of tumor growth in vivo, which was mediated, at least partially, through dual-suppression of PI3K/AKT/mTOR pathway. This finding not only helps us understand the molecular mechanism of endometrial carcinogenesis, but also gives us a strong rationale to further investigate miR-99a as a potential biomarker and therapeutic target for EC.

Molecular pathogenesis of ovarian clear cell carcinoma

Ovarian clear cell carcinoma is a distinct subtype of epithelial ovarian cancer, characterized by an association with endometriosis, glycogen accumulation and resistance to chemotherapy. Key driver events, including ARID1A mutations and HNF1B overexpression, have been recently identified and their functional characterization is ongoing. Additionally, the role of glycogen in promoting the malignant phenotype is coming under scrutiny. Appreciation of the notion that ovarian clear cell carcinoma is essentially an ectopic uterine cancer will hopefully lead to improved animal models of the disease, in turn paving the way for effective treatments.

Targeting therapeutic liabilities engendered by PIK3R1 mutations for cancer treatment

The regulatory subunit of PI3K, p85α (encoded by PIK3R1), binds, stabilizes and inhibits the PI3K p110 catalytic subunit. Functional characterization of PIK3R1 mutations has identified not only hypomorphs with reduced inhibition of p110, but also hypomorphs and dominant negative mutants that disrupt a novel regulatory role of p85α on PTEN or neomorphs that activate unexpected signaling pathways. The diverse phenotypic spectrum of these PIK3R1 driver mutations underscores the need for different treatment strategies targeting tumors harboring these mutations. This article describes the functional consequences of the spectrum of PIK3R1 driver mutations and therapeutic liabilities they may engender.

The microtubule-associated molecular pathways may be genetically disrupted in patients with Bipolar Disorder. Insights from the molecular cascades

Bipolar Disorder is a severe disease characterized by pathological mood swings from major depressive episodes to manic ones and vice versa. The biological underpinnings of Bipolar Disorder have yet to be defined. As a consequence, pharmacological treatments are suboptimal. In the present paper we test the hypothesis that the molecular pathways involved with the direct targets of lithium, hold significantly more genetic variations associated with BD. A molecular pathway approach finds its rationale in the polygenic nature of the disease. The pathways were tested in a sample of ∼ 7,000 patients and controls. Data are available from the public NIMH database. The definition of the pathways was conducted according to the National Cancer Institute (http://pid.nci.nih.gov/). As a result, 3 out of the 18 tested pathways related to lithium action resisted the permutation analysis and were found to be associated with BD. These pathways were related to Reelin, Integrins and Aurora. A pool of genes selected from the ones linked with the above pathways was further investigated in order to identify the fine molecular mechanics shared by our significant pathways and also their link with lithium mechanism of action. The data obtained point out to a possible involvement of microtubule-related mechanics.

PIK3R1 targeting by miR-21 suppresses tumor cell migration and invasion by reducing PI3K/AKT signaling and reversing EMT, and predicts clinical outcome of breast cancer

We have previously shown that dysregulation of miR-21 functioned as an oncomiR in breast cancer. The aim of the present study was to elucidate the mechanisms by which miR-21 regulate breast tumor migration and invasion. We applied pathway analysis on genome microarray data and target-predicting algorithms for miR-21 target screening, and used luciferase reporting assay to confirm the direct target. Thereafter, we investigated the function of the target gene phosphoinositide-3-kinase, regulatory subunit 1 (α) (PIK3R1), and detected PIK3R1 coding protein (p85α) by immunohistochemistry and miR-21 by RT-qPCR on 320 archival paraffin-embedded tissues of breast cancer to evaluate the correlation of their expression with prognosis. First, we found that PIK3R1 suppressed growth, invasiveness, and metastatic properties of breast cancer cells. Next, we identified the PIK3R1 as a direct target of miR-21 and showed that it was negatively regulated by miR-21. Furthermore, we demonstrated that p85α overexpression phenocopied the suppression effects of antimiR-21 on breast cancer cell growth, migration and invasion, indicating its tumor suppressor role in breast cancer. On the contrary, PIK3R1 knockdown abrogated antimiR‑21-induced effect on breast cancer cells. Notably, antimiR-21 induction increased p85α, accompanied by decreased p-AKT level. Besides, antimiR-21/PIK3R1-induced suppression of invasiveness in breast cancer cells was mediated by reversing epithelial-mesenchymal transition (EMT). p85α downregulation was found in 25 (7.8%) of the 320 breast cancer patients, and was associated with inferior 5-year disease-free survival (DFS) and overall survival (OS). Taken together, we provide novel evidence that miR-21 knockdown suppresses cell growth, migration and invasion partly by inhibiting PI3K/AKT activation via direct targeting PIK3R1 and reversing EMT in breast cancer. p85α downregulation defined a specific subgroup of breast cancer with shorter 5-year DFS and OS, which may require more aggressive treatment.

Identification of Variant-Specific Functions of PIK3CA by Rapid Phenotyping of Rare Mutations

Large-scale sequencing efforts are uncovering the complexity of cancer genomes, which are composed of causal "driver" mutations that promote tumor progression along with many more pathologically neutral "passenger" events. The majority of mutations, both in known cancer drivers and uncharacterized genes, are generally of low occurrence, highlighting the need to functionally annotate the long tail of infrequent mutations present in heterogeneous cancers. Here we describe a mutation assessment pipeline enabled by high-throughput engineering of molecularly barcoded gene variant expression clones identified by tumor sequencing. We first used this platform to functionally assess tail mutations observed in PIK3CA, which encodes the catalytic subunit alpha of the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) frequently mutated in cancer. Orthogonal screening for PIK3CA variant activity using in vitro and in vivo cell growth and transformation assays differentiated driver from passenger mutations, revealing that PIK3CA variant activity correlates imperfectly with its mutation frequency across breast cancer populations. Although PIK3CA mutations with frequencies above 5% were significantly more oncogenic than wild-type in all assays, mutations occurring at 0.07% to 5.0% included those with and without oncogenic activities that ranged from weak to strong in at least one assay. Proteomic profiling coupled with therapeutic sensitivity assays on PIK3CA variant-expressing cell models revealed variant-specific activation of PI3K signaling as well as other pathways that include the MEK1/2 module of mitogen-activated protein kinase pathway. Our data indicate that cancer treatments will need to increasingly consider the functional relevance of specific mutations in driver genes rather than considering all mutations in drivers as equivalent.

ARID1A gene mutation in ovarian and endometrial cancers (Review)

The AT-rich interacting domain-containing protein 1A gene (ARID1A) encodes ARID1A, a member of the SWI/SNF chromatin remodeling complex. Mutation of ARID1A induces changes in expression of multiple genes (CDKN1A, SMAD3, MLH1 and PIK3IP1) via chromatin remodeling dysfunction, contributes to carcinogenesis, and has been shown to cause transformation of cells in association with the PI3K/AKT pathway. Information on ARID1A has emerged from comprehensive genome-wide analyses with next-generation sequencers. ARID1A mutations have been found in various types of cancer and occur at high frequency in endometriosis-associated ovarian cancer, including clear cell adenocarcinoma and endometrioid adenocarcinoma, and also occur at endometrial cancer especially in endometrioid adenocarcinoma. It has also been suggested that ARID1A mutation occurs at the early stage of canceration from endometriosis to endometriosis-associated carcinoma in ovarian cancer and also from atypical endo-metrial hyperplasia to endometrioid adenocarcinoma in endometrial cancer. Therefore, development of a screening method that can detect mutations of ARID1A and activation of the PI3K/AKT pathway might enable early diagnosis of endometriosis-associated ovarian cancers and endometrial cancers. Important results may also emerge from a current clinical trial examining a multidrug regimen of temsirolimus, a small molecule inhibitor of the PI3K/AKT pathway, for treatment of advanced ovarian clear cell adenocarcinoma with ARID1A mutation and PI3K/AKT pathway activation. Also administration of sorafenib, a multikinase inhibitor, can inhibit cancer proliferation with PIK3CA mutation and resistance to mTOR inhibitors and GSK126, a molecular-targeted drug can inhibit proliferation of ARID1A-mutated ovarian clear cell adenocarcinoma cells by targeting and inhibiting EZH2. Further studies are needed to determine the mechanism of chromatin remodeling dysregulation initiated by ARID1A mutation, to develop methods for early diagnosis, to investigate new cancer therapy targeting ARID1A, and to examine the involvement of ARID1A mutations in development, survival and progression of cancer cells.

Characterisation of mutations of the phosphoinositide-3-kinase regulatory subunit, PIK3R2, in perisylvian polymicrogyria: a next-generation sequencing study

Background

Bilateral perisylvian polymicrogyria (BPP), the most common form of regional polymicrogyria, causes the congenital bilateral perisylvian syndrome, featuring oromotor dysfunction, cognitive impairment and epilepsy. BPP is etiologically heterogeneous, but only a few genetic causes have been reported. The aim of this study was to identify additional genetic etiologies of BPP and delineate their frequency in this patient population.

Methods

We performed child-parent (trio)-based whole exome sequencing (WES) on eight children with BPP. Following the identification of mosaic PIK3R2 mutations in two of these eight children, we performed targeted screening of PIK3R2 in a cohort of 118 children with BPP who were ascertained from 1980 until 2015 using two methods. First, we performed targeted sequencing of the entire PIK3R2 gene by single molecule molecular inversion probes (smMIPs) on 38 patients with BPP with normal-large head size. Second, we performed amplicon sequencing of the recurrent PIK3R2 mutation (p.Gly373Arg) on 80 children with various types of polymicrogyria including BPP. One additional patient underwent clinical WES independently, and was included in this study given the phenotypic similarity to our cohort. All patients included in this study were children (< 18 years of age) with polymicrogyria enrolled in our research program.

Findings

Using WES, we identified a mosaic mutation (p.Gly373Arg) in the regulatory subunit of the PI3K-AKT-MTOR pathway, PIK3R2, in two children with BPP. Of the 38 patients with BPP and normal-large head size who underwent targeted next generation sequencing by smMIPs, we identified constitutional and mosaic PIK3R2 mutations in 17 additional children. In parallel, one patient was found to have the recurrent PIK3R2 mutation by clinical WES. Seven patients had BPP alone, and 13 had BPP in association with features of the megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome (MPPH). Nineteen patients had the same mutation (Gly373Arg), and one had a nearby missense mutation (p.Lys376Glu). Across the entire cohort, mutations were constitutional in 12 and mosaic in eight patients. Among mosaic patients, we observed substantial variation in alternate (mutant) allele levels ranging from 2·5% (10/377) to 36·7% (39/106) of reads, equivalent to 5–73·4% of cells analyzed. Levels of mosaicism varied from undetectable to 17·1% (37/216) of reads in blood-derived compared to 29·4% (2030/6889) to 43·3% (275/634) in saliva-derived DNA.

Interpretation

Constitutional and mosaic mutations in the PIK3R2 gene are associated with a spectrum of developmental brain disorders ranging from BPP with a normal head size to the megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome. The phenotypic variability and low-level mosaicism challenging conventional molecular methods have important implications for genetic testing and counseling.

A functional module-based exploration between inflammation and cancer in esophagus

Inflammation contributing to the underlying progression of diverse human cancers has been generally appreciated, however, explorations into the molecular links between inflammation and cancer in esophagus are still at its early stage. In our study, we presented a functional module-based approach, in combination with multiple data resource (gene expression, protein-protein interactions (PPI), transcriptional and post-transcriptional regulations) to decipher the underlying links. Via mapping differentially expressed disease genes, functional disease modules were identified. As indicated, those common genes and interactions tended to play important roles in linking inflammation and cancer. Based on crosstalk analysis, we demonstrated that, although most disease genes were not shared by both kinds of modules, they might act through participating in the same or similar functions to complete the molecular links. Additionally, we applied pivot analysis to extract significant regulators for per significant crosstalk module pair. As shown, pivot regulators might manipulate vital parts of the module subnetworks, and then work together to bridge inflammation and cancer in esophagus. Collectively, based on our functional module analysis, we demonstrated that shared genes or interactions, significant crosstalk modules, and those significant pivot regulators were served as different functional parts underlying the molecular links between inflammation and cancer in esophagus.

Assembly and Molecular Architecture of the Phosphoinositide 3-Kinase p85α Homodimer

Phosphoinositide 3-kinases (PI3Ks) are a family of lipid kinases that are activated by growth factor and G-protein-coupled receptors and propagate intracellular signals for growth, survival, proliferation, and metabolism. p85α, a modular protein consisting of five domains, binds and inhibits the enzymatic activity of class IA PI3K catalytic subunits. Here, we describe the structural states of the p85α dimer, based on data from in vivo and in vitro solution characterization. Our in vitro assembly and structural analyses have been enabled by the creation of cysteine-free p85α that is functionally equivalent to native p85α. Analytical ultracentrifugation studies showed that p85α undergoes rapidly reversible monomer-dimer assembly that is highly exothermic in nature. In addition to the documented SH3-PR1 dimerization interaction, we identified a second intermolecular interaction mediated by cSH2 domains at the C-terminal end of the polypeptide. We have demonstrated in vivo concentration-dependent dimerization of p85α using fluorescence fluctuation spectroscopy. Finally, we have defined solution conditions under which the protein is predominantly monomeric or dimeric, providing the basis for small angle x-ray scattering and chemical cross-linking structural analysis of the discrete dimer. These experimental data have been used for the integrative structure determination of the p85α dimer. Our study provides new insight into the structure and assembly of the p85α homodimer and suggests that this protein is a highly dynamic molecule whose conformational flexibility allows it to transiently associate with multiple binding proteins.

PTEN loss is a context-dependent outcome determinant in obese and non-obese endometrioid endometrial cancer patients

Endometrial cancer incidence is increasing, due in part to a strong association with obesity. Mutations in the phosphatidylinositol 3-kinase (PI3K) pathway, the central relay pathway of insulin signals, occur in the majority of endometrioid adenocarcinomas, the most common form of endometrial cancer. We sought to determine the impact of PI3K pathway alterations on progression free survival in a cohort of endometrioid endometrial cancers. Prognostic utility of PIK3CA, PIK3R1, and PTEN mutations, as well as PTEN protein loss by immunohistochemistry, was explored in the context of patient body mass index. Reverse-phase protein arrays were utilized to assess protein expression based on PTEN status. Among 187 endometrioid endometrial cancers, there were no statistically significant associations between PFS and PIK3CA, PIK3R1, PTEN mutation or loss. When stratified by body mass index, PTEN loss was associated with improved progression free survival (P < 0.006) in obese (body mass index ≥ 30) patients. PTEN loss resulted in distinct protein changes: Canonical PI3K pathway activation was observed only in the non-obese population while decreased expression of β-CATENIN and phosphorylated FOXO3A was observed in obese patients. These data suggest the impact of PTEN loss on tumor biology and clinical outcomes must be interpreted in the context of body mass index, and provide a potential explanation for discrepant reports on the effect of PTEN status and obesity on prognosis in endometrial cancer. This reveals a clinically important interaction between metabolic state and tumor genetics that may unveil the biologic underpinning of obesity-related cancers and impact ongoing clinical trials with PI3K pathway inhibitors.

Emerging strategies for targeting PI3K in gynecologic cancer

Ovarian, endometrial and cervical cancers are the most prevalent gynecologic cancers in the United States and account for significant mortality. Translational research into these cancers has highlighted the distinctive molecular and genomic profiles of these cancers finding that, even within a disease site, the landscapes and drivers of neoplasia are distinctive. Despite this molecular diversity, activation of the phosphatidylinositol-3-kinase (PI3K) pathway appears to be conserved in subsets of these tumors, suggesting that strategies that antagonize mediators in this signaling cascade could offer anti-tumor efficacy. Extensive pre-clinical and clinical data have demonstrated that single agent targeted therapies lead to modest single agent activity of generally limited duration, even in the setting of innate PI3K pathway activation via mutation or amplification. These findings in the laboratory and clinic have prompted investigations into resistance pathways following PI3K pathway inhibition in order to understand escape pathways and restore tumor cell sensitivity. A next generation of clinical trial investigations will focus on novel combinations in order to define how these important therapeutics can be used in the clinic. This review will present preclinical data that supports the role of the PI3K pathway in ovarian, endometrial and cervical cancers, in addition to discussing the reported clinical trial experience with PI3K pathway inhibition. A specific focus will be on the rationale behind ongoing clinical trials utilizing novel agents in concert with PI3K pathway inhibitors to reverse resistance in populations with and without gain of function alterations in this oncogenic signaling cascade.

An Optimization-Driven Analysis Pipeline to Uncover Biomarkers and Signaling Paths: Cervix Cancer

Establishing how a series of potentially important genes might relate to each other is relevant to understand the origin and evolution of illnesses, such as cancer. High-throughput biological experiments have played a critical role in providing information in this regard. A special challenge, however, is that of trying to conciliate information from separate microarray experiments to build a potential genetic signaling path. This work proposes a two-step analysis pipeline, based on optimization, to approach meta-analysis aiming to build a proxy for a genetic signaling path.

Analysis of differentially expressed genes between endometrial carcinosarcomas and endometrioid endometrial carcinoma by bioinformatics

PURPOSE

This study aimed to explore the underlying molecular mechanisms of endometrial carcinosarcomas (ECS) and endometrioid endometrial carcinoma (EEC) by bioinformatics analysis.

METHODS

Gene expression profile GSE33723 was downloaded from the Gene Expression Omnibus. A total of 15 ECS and 23 EEC samples were used to identify the differentially expressed genes (DEGs) by significance analysis of microarrays. After construction of protein-protein interaction (PPI) network, Gene Ontology (GO) functional and pathway enrichment analyses of DEGs were performed, followed by network module analysis.

RESULTS

A total of 49 DEGs were identified between EEC and ECS samples. In the PPI network, TP53 (tumor protein p53) was selected as the highest degree, hub centrality and betweenness. The top 10 enriched GO terms including regulation of cell death and top 10 significant pathways including cell cycle were selected. After network module analysis, PIK3R1 (phosphoinositide-3-kinase, regulatory subunit 1) and AKT2 (v-akt murine thymoma viral oncogene homolog 2) were selected as the co-expressed genes in the states of ECS while STAT3 (signal transducer and activator of transcription 3) and JAZF (JAZF zinc finger 1) were selected as the co-expressed genes in the states of EEC.

CONCLUSIONS

The DEGs, such as TP53, PIK3R1 and AKT2 may be used for targeted diagnosis and treatment of ECS while STAT3 and JAZF1 may be served as a target for EEC.

Improved survival associated with somatic PIK3CA mutations in copy-number low endometrioid endometrial adenocarcinoma

The phosphoinositide-3-kinase (PI3K) signaling pathway has been implicated in the development of endometrioid endometrial adenocarcinoma (EEC). Recently, The Cancer Genome Atlas (TCGA) project stratified EEC into four molecular subgroups, with the majority of tumors falling into the copy-number low-EEC (CNL-EEC) molecular subgroup. The aim of the present study was to investigate whether alterations of the PI3K pathway are associated with specific survival outcomes in patients with EEC. The clinical and genomic data of 307 patients with endometrioid-type tumors were obtained from TCGA project, including 90 patients in the CNL-EEC subgroup. Patients were evaluated in terms of survival and clinicopathological characteristics, as well as mutations in the PI3K catalytic subunit alpha (PIK3CA) gene and their effect on PIK3CA function. In CNL-EEC subgroup patients, somatic PIK3CA mutations (48/90 cases) were associated with significantly improved overall survival compared with that of wild-type PIK3CA (P=0.018). Furthermore, this improved survival was specific to the CNL-EEC subgroup and was not observed in other TCGA molecular subgroups. The majority of CNL-EEC cases were low-stage (stage I) and low-to-intermediate grade (grades 1–2) endometrioid tumors. There were no significant differences in age, stage, histology or International Federation of Gynecology and Obstetrics grade between PIK3CA-mutated and non-mutated patient groups (P>0.05). In addition, the majority of cases contained activating PIK3CA mutations. Overall, in the TCGA cohort, PIK3CA mutations had a favorable effect on the survival of patients with EEC, and this effect was dependent on tumoral molecular sub-stratification. Future studies on larger independent cohorts with long term follow-up are warranted to further analyze this association.

Systematic Analysis of Endometrial Cancer-Associated Hub Proteins Based on Text Mining

Objective. The aim of this study was to systematically characterize the expression of endometrial cancer- (EC-) associated genes and to analysis the functions, pathways, and networks of EC-associated hub proteins. Methods. Gene data for EC were extracted from the PubMed (MEDLINE) database using text mining based on NLP. PPI networks and pathways were integrated and obtained from the KEGG and other databases. Proteins that interacted with at least 10 other proteins were identified as the hub proteins of the EC-related genes network. Results. A total of 489 genes were identified as EC-related with P < 0.05, and 32 pathways were identified as significant (P < 0.05, FDR < 0.05). A network of EC-related proteins that included 271 interactions was constructed. The 17 proteins that interact with 10 or more other proteins (P < 0.05, FDR < 0.05) were identified as the hub proteins of this PPI network of EC-related genes. These 17 proteins are EGFR, MET, PDGFRB, CCND1, JUN, FGFR2, MYC, PIK3CA, PIK3R1, PIK3R2, KRAS, MAPK3, CTNNB1, RELA, JAK2, AKT1, and AKT2. Conclusion. Our data may help to reveal the molecular mechanisms of EC development and provide implications for targeted therapy for EC. However, corrections between certain proteins and EC continue to require additional exploration.

Inactivation of tumor suppressor gene pten in early and advanced gallbladder cancer

Background

PTEN is a tumor suppressor gene that regulates the PTEN/PI3k/AKT/mTOR pathway, which is frequently altered in human cancers including gallbladder cancer (GBC). To determine the frequency of PTEN expression in GBC and to establish its relation to clinical and morphological parameters and survival in GBC.

Methods

The immunohistochemical expression of PTEN was studied in 108 GBC. All the cases included areas of non-tumor mucosa adjacent to the tumor.

Results

The group was comprised of 108 patients, 91 women (84.3 %) and 17 men (15.7 %) with an average age of 65.2 years (SD ± 12.3 years). Thirty-five cases (33 %) were early carcinomas (EC) and the remaining 73 (67 %) were advanced cases (AC). All the internal controls were positive (moderate or intense in 96.3 %). Only in three AC (4.1 %) was there a complete absence of PTEN immunohistochemical expression. There were no significant differences in relation between PTEN expression and tumor infiltration or degree of differentiation. The three patients with PTEN inactivation died before 10 months; however, the other patients with AC had a survival of 53 % at 10 months.

Discussion

Loss of PTEN expression was observed in 4.1 % of the advanced GBC. All the patients with this alteration died before 10 months. PTEN inactivation could be a rare event, but with a poor prognosis in advanced GBC.

Regulation of the PI3K pathway through a p85α monomer-homodimer equilibrium

The canonical action of the p85α regulatory subunit of phosphatidylinositol 3-kinase (PI3K) is to associate with the p110α catalytic subunit to allow stimuli-dependent activation of the PI3K pathway. We elucidate a p110α-independent role of homodimerized p85α in the positive regulation of PTEN stability and activity. p110α-free p85α homodimerizes via two intermolecular interactions (SH3:proline-rich region and BH:BH) to selectively bind unphosphorylated activated PTEN. As a consequence, homodimeric but not monomeric p85α suppresses the PI3K pathway by protecting PTEN from E3 ligase WWP2-mediated proteasomal degradation. Further, the p85α homodimer enhances the lipid phosphatase activity and membrane association of PTEN. Strikingly, we identified cancer patient-derived oncogenic p85α mutations that target the homodimerization or PTEN interaction surface. Collectively, our data suggest the equilibrium of p85α monomer-dimers regulates the PI3K pathway and disrupting this equilibrium could lead to disease development.

The PI3K/AKT Pathway and Renal Cell Carcinoma

The phosphatidylinositol 3 kinase (PI3K)/AKT pathway is genetically targeted in more pathway components and in more tumor types than any other growth factor signaling pathway, and thus is frequently activated as a cancer driver. More importantly, the PI3K/AKT pathway is composed of multiple bifurcating and converging kinase cascades, providing many potential targets for cancer therapy. Renal cell carcinoma (RCC) is a high-risk and high-mortality cancer that is notoriously resistant to traditional chemotherapies or radiotherapies. The PI3K/AKT pathway is modestly mutated but highly activated in RCC, representing a promising drug target. Indeed, PI3K pathway inhibitors of the rapalog family are approved for use in RCC. Recent large-scale integrated analyses of a large number of patients have provided a molecular basis for RCC, reiterating the critical role of the PI3K/AKT pathway in this cancer. In this review, we summarize the genetic alterations of the PI3K/AKT pathway in RCC as indicated in the latest large-scale genome sequencing data, as well as treatments for RCC that target the aberrant activated PI3K/AKT pathway.

Glucose promotes cell proliferation, glucose uptake and invasion in endometrial cancer cells via AMPK/mTOR/S6 and MAPK signaling

OBJECTIVES

Obesity and diabetes are well-known risk factors for the development of endometrial cancer. A high rate of aerobic glycolysis represents a key mechanism by which endometrial cancer cells consume glucose as its primary energy source. The up-regulated glycolytic pathway is a common therapeutic target whose inhibition has implications for anti-tumor activity in cancer cells. This study aimed to investigate the effect of various concentrations of glucose on cell proliferation in endometrial cancer.

METHODS

ECC-1 and Ishikawa cells were treated with low glucose (1mM), normal glucose (5mM) and high glucose (25mM), and cytotoxicity, apoptosis, cell cycle, adhesion/invasion, and changes of AMPK/mTOR/S6 and MAPK pathways were evaluated.

RESULTS

Our results revealed that high glucose increased cell growth and clonogenicity in two endometrial cancer cell lines in a dose dependent manner. Low glucose induced the activity of cleaved caspase 3 and caused cell cycle G1 arrest. High glucose increased the ability of adhesion and invasion by decreasing E-cadherin and increasing Snail expression. In addition, high glucose increased glucose uptake and glycolytic activity through modulating the AMPK/mTOR/S6 and MAPK pathways.

CONCLUSIONS

Our findings suggest that glucose stimulated cell proliferation through multiple complex signaling pathways. Targeting glucose metabolism may be a promising therapeutic strategy in the treatment of endometrial cancer.

Inferring pathway dysregulation in cancers from multiple types of omic data

Although in some cases individual genomic aberrations may drive disease development in isolation, a complex interplay among multiple aberrations is common. Accordingly, we developed Gene Set Omic Analysis (GSOA), a bioinformatics tool that can evaluate multiple types and combinations of omic data at the pathway level. GSOA uses machine learning to identify dysregulated pathways and improves upon other methods because of its ability to decipher complex, multigene patterns. We compare GSOA to alternative methods and demonstrate its ability to identify pathways known to play a role in various cancer phenotypes. Software implementing the GSOA method is freely available from https://bitbucket.org/srp33/gsoa.

WWP2 and its association with PTEN in endometrial cancer

We wished to determine if WWP2 gene expression and PTEN protein levels inversely correlate in human endometrial cancer tissues. Fifty-one endometrioid endometrial tumors and five normal endometrial controls were available for analysis. PTEN protein levels were assessed by immunohistochemistry (IHC). WWP2 and PTEN gene expression were quantitated by RT PCR. Clinical and pathologic information was collected by chart review.

We found that in tumors with low PTEN protein but normal mRNA expression there were significantly higher levels of WWP2 expression (p = 0.0017). Increased WWP2 expression was not associated with clinical prognostic factors including lymphovascular space invasion, ≥ 50% myometrial invasion, grade, stage or recurrence. WWP2 expression was not different statistically between tumors and normal controls (p = NS). Therefore, in this cohort, tumors with low PTEN protein but normal mRNA expression had elevated levels of WWP2 expression. This suggests that WWP2 may be playing a role in PTEN degradation in endometrial cancer.

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WWP2 is a ubiquitin ligase shown to degrade PTEN in previous studies.

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We investigated WWP2 levels in endometrial cancers.

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WWP2 levels in tumors with normal gene expression but loss of PTEN protein on IHC were compared to tumors without PTEN protein loss on IHC.

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WWP2 levels were significantly higher in tumors with normal gene expression but loss of PTEN protein on IHC

High-throughput oncogene mutation profiling shows demographic differences in BRAF mutation rates among melanoma patients

Because of advances in targeted therapies, the clinical evaluation of cutaneous melanoma is increasingly based on a combination of traditional histopathology and molecular pathology. Therefore, it is necessary to expand our knowledge of the molecular events that accompany the development and progression of melanoma to optimize clinical management. The central objective of this study was to increase our knowledge of the mutational events that complement melanoma progression. High-throughput genotyping was adapted to query 159 known single nucleotide mutations in 33 cancer-related genes across two melanoma cohorts from Ireland (n=94) and Belgium (n=60). Results were correlated with various clinicopathological characteristics. A total of 23 mutations in 12 genes were identified, that is--BRAF, NRAS, MET, PHLPP2, PIK3R1, IDH1, KIT, STK11, CTNNB1, JAK2, ALK, and GNAS. Unexpectedly, we discovered significant differences in BRAF, MET, and PIK3R1 mutations between the cohorts. That is, cases from Ireland showed significantly lower (P<0.001) BRAF(V600E) mutation rates (19%) compared with the mutation frequency observed in Belgian patients (43%). Moreover, MET mutations were detected in 12% of Irish cases, whereas none of the Belgian patients harbored these mutations, and Irish patients significantly more often (P=0.027) had PIK3R1-mutant (33%) melanoma versus 17% of Belgian cases. The low incidence of BRAF(V600E)(-) mutant melanoma among Irish patients was confirmed in five independent Irish cohorts, and in total, only 165 of 689 (24%) Irish cases carried mutant BRAF(V600E). Together, our data show that melanoma-driving mutations vary by demographic area, which has important implications for the clinical management of this disease.

p85α neomorphic mutants: splitting away from the canonical path

PIK3R1 (encoding the p85α subunit of phosphatidylinositol 3-kinase) is the 11th most frequently mutated gene across tumors. We recently reported neomorphic p85α mutants that induce signaling cascades not predicted by the canonical functions of p85α, suggesting the need to functionally annotate specific mutations in cancer genes for effective genome-informed personalized therapy.

Second-line dovitinib (TKI258) in patients with FGFR2-mutated or FGFR2-non-mutated advanced or metastatic endometrial cancer: a non-randomised, open-label, two-group, two-stage, phase 2 study

BACKGROUND

Activating FGFR2 mutations are found in 10-16% of primary endometrial cancers and provide an opportunity for targeted therapy. We assessed the safety and activity of dovitinib, a potent tyrosine-kinase inhibitor of fibroblast growth factor receptors, VEGF receptors, PDGFR-β, and c-KIT, as second-line therapy both in patients with FGFR2-mutated (FGFR2(mut)) endometrial cancer and in those with FGFR2-non-mutated (FGFR2(non-mut)) endometrial cancer.

METHODS

In this phase 2, non-randomised, two-group, two-stage study, we enrolled adult women who had progressive disease after first-line chemotherapy for advanced or metastatic endometrial cancer from 46 clinical sites in seven countries. We grouped women according to FGFR2 mutation status and gave all women dovitinib (500 mg per day, orally, on a 5-days-on and 2-days-off schedule) until disease progression, unacceptable toxicity, death, or study discontinuation for any other reason. The primary endpoint was proportion of patients in each group who were progression-free at 18 weeks. For each group, the second stage of the trial (enrolment of 20 additional patients) could proceed if at least eight of the first 20 treated patients were progression free at 18 weeks. Activity was assessed in all enrolled patients and safety was assessed in all patients who received at least one dose of dovitinib. The completed study is registered with ClinicalTrials.gov, number NCT01379534.

FINDINGS

Of 248 patients with FGFR2 prescreening results, 27 (11%) had FGFR2(mut) endometrial cancer. Between Feb 17, 2012, and Dec 13, 2013, we enrolled 22 patients in the FGFR2(mut) group and 31 patients in the FGFR2(non-mut) group. Seven (31·8%, 95% CI 13·9-54·9) patients in the FGFR2(mut) group and nine (29·0%, 14·2-48·0) in the FGFR2(non-mut) group were progression-free at 18 weeks. On the basis of predefined criteria, neither group continued to stage two: seven (35%) of the first 20 patients in the FGFR2(mut) group were progression free at 18 weeks, as were five (25%) of the first 20 in the FGFR2(mut) population. Rates of treatment-emergent adverse events were similar between groups and events were most frequently gastrointestinal. Overall, the most common grade 3 or 4 adverse events suspected to be related to the study drug were hypertension (nine patients; 17%) and diarrhoea (five; 9%). The most frequently reported serious adverse events suspected to be related to study drug were pulmonary embolism (four patients; 8%), vomiting (four; 8%), dehydration (three; 6%), and diarrhoea (three; 6%). Only one death was deemed to be treatment-related: one patient in the FGFR2(non-mut) group died from cardiac arrest with contributing reason of pulmonary embolism (grade 4, suspected to be study drug related) 4 days previously.

INTERPRETATION

Second-line dovitinib in FGFR2(mut) and FGFR2(non-mut) advanced or metastatic endometrial cancer had single-agent activity, although it did not reach the prespecified study criteria. Observed treatment effects seemed independent of FGFR2 mutation status. These data should be considered exploratory and additional studies are needed.

FUNDING

Novartis Pharmaceuticals.

Deregulation of the EGFR/PI3K/PTEN/Akt/mTORC1 pathway in breast cancer: possibilities for therapeutic intervention

The EGFR/PI3K/PTEN/Akt/mTORC1/GSK-3 pathway plays prominent roles in malignant transformation, prevention of apoptosis, drug resistance and metastasis. The expression of this pathway is frequently altered in breast cancer due to mutations at or aberrant expression of: HER2, ERalpha, BRCA1, BRCA2, EGFR1, PIK3CA, PTEN, TP53, RB as well as other oncogenes and tumor suppressor genes. In some breast cancer cases, mutations at certain components of this pathway (e.g., PIK3CA) are associated with a better prognosis than breast cancers lacking these mutations. The expression of this pathway and upstream HER2 has been associated with breast cancer initiating cells (CICs) and in some cases resistance to treatment. The anti-diabetes drug metformin can suppress the growth of breast CICs and herceptin-resistant HER2+ cells. This review will discuss the importance of the EGFR/PI3K/PTEN/Akt/mTORC1/GSK-3 pathway primarily in breast cancer but will also include relevant examples from other cancer types. The targeting of this pathway will be discussed as well as clinical trials with novel small molecule inhibitors. The targeting of the hormone receptor, HER2 and EGFR1 in breast cancer will be reviewed in association with suppression of the EGFR/PI3K/PTEN/Akt/mTORC1/GSK-3 pathway.

Metformin and gynecologic cancers

IMPORTANCE

The obese population in the United States is reaching epic proportions, and obesity is linked to an increased risk for several cancers including gynecologic cancers. Obesity is not only a risk factor but also a marker of poor prognosis. It is crucial to develop novel treatment strategies to target this population. Metformin is a biguanide drug, typically used for diabetes treatment, currently being studied to evaluate its role in the treatment and prevention of gynecologic cancers.

OBJECTIVE

The aim of this study was to review the underlying biologic mechanisms of metformin's antitumorigenic effects. We assessed the epidemiologic and preclinical data that support the use of metformin in patients with endometrial and ovarian cancer. Finally, we reviewed current clinical trials that incorporate metformin as a prevention or treatment strategy for gynecologic cancers.

EVIDENCE ACQUISITION

A thorough search of PubMed for all current literature was performed. All preclinical, clinical, and epidemiologic reviews were evaluated across all cancers, with a focus on gynecologic cancer.

RESULTS

The preclinical, epidemiologic, and clinical data evaluated in this review are strongly supportive of the use of metformin for the prevention and treatment of gynecologic cancer. On the basis of these data, centers are currently enrolling for clinical trials using metformin in patients diagnosed with gynecologic malignancies.

CONCLUSIONS AND RELEVANCE

The data supporting the use of metformin in the prevention and treatment of cancers are building, including that of endometrial and ovarian cancer. The association between obesity, insulin resistance, as well as increased risk and poor outcomes in endometrial and ovarian cancer patients makes metformin an attractive agent for the prevention and treatment of these diseases.

miR-128-3p suppresses hepatocellular carcinoma proliferation by regulating PIK3R1 and is correlated with the prognosis of HCC patients

microRNAs (miRNAs) are known to be involved in the pathogenesis of hepatocellular carcinoma (HCC). miR-128-3p was recently reported to be deregulated in several types of cancer. However, the biological function and potential mechanisms of miR-128-3p in HCC remain unknown. In the present study, we found that miR-128-3p was frequently downregulated in HCC tissues and cell lines by qRT-PCR analysis. Moreover, functional assays showed that overexpression of miR-128-3p markedly suppressed HCC cell proliferation by inducing G1 phase cell arrest and migration. Mechanistically, miR-128-3p was confirmed to regulate PIK3R1 (p85α) expression thereby suppressing phosphatidylinositol 3-kinase (PI3K)/AKT pathway activation using qRT-PCR and western blot analysis. Furthermore, correlation analysis and Kaplan-Meier estimates revealed an inverse correlation between miR-128-3p and p85α as well as a shorter disease-free survival (DFS) period after HCC resection in patients with low miR-128-3p expression. Hence, we conclude that miR-128-3p, which is frequently downregulated in HCC, inhibits HCC progression by regulating PIK3R1 and PI3K/AKT activation, and is a prognostic marker for HCC patients.

PTEN Expression as a Predictor of Response to Focal Adhesion Kinase Inhibition in Uterine Cancer

PTEN is known to be frequently mutated in uterine cancer and also dephosphorylates FAK. Here, we examined the impact of PTEN alterations on the response to treatment with a FAK inhibitor (GSK2256098). In vitro and in vivo therapeutic experiments were carried out using PTEN-mutated and PTEN-wild-type models of uterine cancer alone and in combination with chemotherapy. Treatment with GSK2256098 resulted in greater inhibition of pFAK(Y397) in PTEN-mutated (Ishikawa) than in PTEN-wild-type (Hec1A) cells. Ishikawa cells were more sensitive to GSK2256098 than the treated Hec1A cells. Ishikawa cells were transfected with a wild-type PTEN construct and pFAK(Y397) expression was unchanged after treatment with GSK2256098. Decreased cell viability and enhanced sensitivity to chemotherapy (paclitaxel and topotecan) in combination with GSK2256098 was observed in Ishikawa cells as compared with Hec1a cells. In the Ishikawa orthoptopic murine model, treatment with GSK2256098 resulted in lower tumor weights and fewer metastases than mice inoculated with Hec1A cells. Tumors treated with GSK2256098 had lower microvessel density (CD31), less cellular proliferation (Ki67), and higher apoptosis (TUNEL) rates in the Ishikawa model when compared with the Hec1a model. From a large cohort of evaluable patients, increased FAK and pFAK(Y397) expression levels were significantly related to poor overall survival. Moreover, PTEN levels were inversely related to pFAK(Y397) expression. These preclinical data demonstrate that PTEN-mutated uterine cancer responds better to FAK inhibition than does PTEN wild-type cancer. Therefore, PTEN could be a biomarker for predicting response to FAK-targeted therapy during clinical development.

Small molecule schweinfurthins selectively inhibit cancer cell proliferation and mTOR/AKT signaling by interfering with trans-Golgi-network trafficking

Natural compound schweinfurthins are of considerable interest for novel therapy development because of their selective anti-proliferative activity against human cancer cells. We previously reported the isolation of highly active schweinfurthins E-H, and in the present study, mechanisms of the potent and selective anti-proliferation were investigated. We found that schweinfurthins preferentially inhibited the proliferation of PTEN deficient cancer cells by indirect inhibition of AKT phosphorylation. Mechanistically, schweinfurthins and their analogs arrested trans-Golgi-network trafficking, an intracellular vesicular trafficking system, resulting in the induction of endoplasmic reticulum stress and the suppression of both lipid raft-mediated PI3K activation and mTOR/RheB complex formation, which collectively led to an effective inhibition of mTOR/AKT signaling. The trans-Golgi-network traffic arresting effect of schweinfurthins was associated with their in vitro binding activity to oxysterol-binding proteins that are known to regulate intracellular vesicular trafficking. Moreover, schweinfurthins were found to be highly toxic toward PTEN-deficient B cell lymphoma cells, and displayed 2 orders of magnitude lower activity toward normal human peripheral blood mononuclear cells and primary fibroblasts in vitro. These results revealed a previously unrecognized role of schweinfurthins in regulating trans-Golgi-network trafficking, and linked mechanistically this cellular effect with mTOR/AKT signaling and with cancer cell survival and growth. Our findings suggest the schweinfurthin class of compounds as a novel approach to modulate oncogenic mTOR/AKT signaling for cancer treatment.