Loss Of PTEN Expression Research Articles

Loss of PTEN expression is associated with PI3K pathway-dependent metabolic reprogramming in hepatocellular carcinoma

BackgroundMetabolic reprogramming, in which energetic metabolism changes from oxidative phosphorylation to glycolysis, is well-accepted as a hallmark of cancers including hepatocellular carcinoma (HCC). A growing body of evidence suggests the involvement of oncogenes and tumor suppressor genes in the control of metabolic reprogramming. In this study, we attempt to investigate whether loss of PTEN, a recognized tumor suppressor, drives metabolic reprogramming of HCC.MethodsCancerous liver tissues were surgically resected from 128 HCC patients, with 43 adjacent noncancerous liver tissues as control. Aerobic glycolysis (Warburg effect) was reflected by measurements of glucose uptake and lactate production, mitochondrial membrane potential collapse was observed by JC-1 staining, glycolytic rate and mitochondrial respiration were evaluated by determining glycolytic proton efflux rate (glycoPER) and oxygen consumption rate (OCR) in cultured human HHCC cells.ResultsReciprocal expression of PTEN and PI3K was determined in cancer liver tissues. Overexpression of PTEN suppressed the Warburg effect, as evidenced by reductions in glucose uptake and lactate production, maintenance of mitochondrial function, and transformation of energetic metabolism from glycolysis to oxidative phosphorylation in cultured PTEN-negative HHCC cells. Importantly, 740 Y-P, a PI3K agonist that leads to activation of the PI3K pathway, partially abrogated the function of PTEN and reprogramed glucose metabolism in cultured HHCC cells.ConclusionsThe discovery that loss of PTEN allows the tumor metabolic program has been a major advance in understanding the carcinogenesis of HCC.Bo7HehjAYW3ADh-U-ymoVNVideo abstractGraphical abstractGraphic abstract showing that loss of PTEN regulates the tumor metabolic program in hepatocellular carcinoma. Loss of PTEN leads to activation of the PI3K pathway enhances the Warburg effect, thereby promoting the development of hepatocellular carcinoma.

The loss of PTEN expression and microsatellite stability (MSS) were predictors of unfavorable prognosis in gastric cancer (GC).

The predictors for the prognosis of gastric cancer (GC) are not clear. We intended to explore the role of PTEN and microsatellite (MS) in GC, showing their potential as prognostic markers. Primary gastric cancer tissues, adjacent normal tissues, and clinicopathological parameters of 187 patients were collected. The expression level of PTEN and MS status were classified by immunohistochemistry (IHC). The relationship among indicators was compared by the chi-square test. The survival curves were delineated by Kaplan-Meier and tested by Log-rank methods. The impact of multiple factors on prognosis was determined by COX proportional hazards model. Significantly, PTEN expression was associated with lymphatic invasion (p=0.011) and Lauren grade (p=0.015). MS status was associated with differentiation (p=0.006) and Lauren grades (p=0.035). TNM stage was associated with MS status under positive PTEN expression (p=0.014). Patients with microsatellite stability (MSS) had worse median overall survival (OS) than that with microsatellite instability (MSI) (p=0.013). Patients with negative PTEN expression had a worse median OS than that with positive PTEN expression (p<0.001). The tumor subtype of PTEN negative-MSS (p<0.001) and PTEN negative-MSI (p=0.042) were strong predictors of poor survival. Negative PTEN expression and MSS might lead to unfavorable prognosis due to their association with clinicopathological parameters of GC. PTEN expression and MS status could be predictors for the prognosis of GC.

Abstract B78: Improving chemotherapy response of immunologically cold high-grade serous ovarian cancer with loss of PTEN using STING agonist

Abstract High-grade serous ovarian carcinoma (HGSC) is the most lethal gynecologic malignancy, with high rates of chemotherapy resistance and poor outcomes. We previously showed that tumors from chemotherapy-resistant patients show an immunologically cold phenotype, exhibiting lower density of CD8+ T cells and low expression of interferon genes. Subsequently, using the ID8-Trp53−/− murine model of HGSC, we further demonstrated the potential of Stimulator of Interferon Genes (STING) pathway activation in enhancing response of HGSC to carboplatin chemotherapy. Currently, we aim to better characterize the effect of cancer cell genotype on response to treatment in HGSC. The evolution of the tumor immune microenvironment (TIME) as immunologically hot or cold can be to some extent dictated by cancer cell-specific genetic alterations. While loss of the tumor suppressor TP53 is a universal mutation (&amp;gt;96% of cases), previous reports in HGSC have shown that patients with BRCA1 mutations (~25% of cases) have higher CD8+ T-cell infiltration and higher chemosensitivity. In contrast, loss of PTEN (seen in ~20% of cases) is associated with poor outcomes and chemoresistance. We hypothesized that HGSC tumors with loss of PTEN expression can benefit via immunomodulatory treatment approaches that activate the STING pathway following chemotherapy. C57/BL6 mice were implanted with either ID8-Trp53−/−; Brca1−/− cells or ID8-Trp53−/−; Pten−/− cells and subjected to one of three treatment groups: vehicle, carboplatin, or carboplatin + STING agonist. Characterization of the TIME generated from ID8-Trp53−/−; Brca1−/− cells, and those from ID8-Trp53−/−; Pten−/− cells, through local and systemic immune profiling, showed significant immunologic differences between different genotypes. Addition of STING agonist significantly increased chemosensitivity and improved overall response in ID8-Trp53−/−; Pten−/− injected mice compared to those treated with carboplatin alone. This study helps to determine the potential of STING pathway activation in inducing an activated tumor immune state in genotypes of HGSC that result in a “cold” TIME, such as loss of PTEN, to augment responses to chemotherapy and prolong survival. Citation Format: Noor Shakfa, Elizabeth Lightbody, Afrakoma Afriyie-Asante, Vinicius Kannen, Madhuri Koti. Improving chemotherapy response of immunologically cold high-grade serous ovarian cancer with loss of PTEN using STING agonist [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr B78.

STING pathway mediated immunologic consequences of DNA damage repair gene losses in high-grade serous ovarian tumors

Abstract High grade serous ovarian carcinoma (HGSC) is the most lethal gynecologic malignancy with high rates of chemotherapy resistance and poor outcomes. Our previous studies have demonstrated the variable tumor immune microenvironment states that associate with platinum chemotherapy response. We further showed the significance of the interferon induced chemokine CXCL10 as a key mediator of tumor infiltrating immune cell recruitment. Using the ID8-Trp53−/− murine model of HGSC, we demonstrated the potential of Stimulator of Interferon Genes (STING) pathway activation in enhancing response of HGSC tumors to carboplatin chemotherapy and sensitizing them to immune checkpoint blockade. Notably, CXCL10 production via IFN1 is also governed by genes that regulate cellular DNA damage repair pathways. Evolving evidence indicates a role of BRCA1 and PTEN genes in mediating cellular IFN1 responses. Losses in the function of these genes is widely prevalent in a large proportion of HGSC tumors, where tumors with BRCA1 mutations have higher CD8+ T cell infiltration in contrast to those with loss of PTEN. We hypothesized that HGSC tumors with loss of PTEN expression can be rendered susceptible to immune mediated killing via activating the STING pathway. Tumors generated from ID8-Trp53−/−; Brca1−/− cells and those from ID8-Trp53−/−; Pten−/− cells in C57BL6 mice showed significant immunologic differences. STING agonist treatment significantly increased chemosensitivity and improved overall response in mice implanted with ID8-Trp53−/−; Pten−/− cells compared to those treated with carboplatin alone, altering immune responses. This study is foundational to guide rationalistic combinations of STING pathway activating therapies in HGSC.

Enhanced immortalization, HUWE1 mutations and other biological drivers of breast invasive carcinoma in Black/African American patients.

Black/African-American (B/AA) breast cancer patients tend to have more aggressive tumor biology compared to White/Caucasians. In this study, a variety of breast tumor molecular expression profiles of patients derived from the two racial groupings were investigated. Breast invasive carcinoma sample data (RNASeq version 2, Reverse Phase Protein Array, mutation, and miRSeq data) from the Cancer Genome Atlas were examined. The results affirm that B/AA patients are more likely than Caucasian patients to harbor the aggressive basal-like or the poor prognosis-associated HER2-enriched molecular subtypes of breast cancer. There is also a higher incidence of the triple-negative breast cancer (TNBC) among B/AA patients than the general population, a fact reflected in the mutation patterns of genes such as PIK3CA and TP53. Furthermore, an immortalization signature gene set, is enriched in samples from B/AA patients. Among stage III patients, TERT, DRAP1, and PQBP1, all members of the immortalization gene signature set, are among master-regulators with increased activity in B/AA patients. Master-regulators driving differences in expression profiles between the two groups include immortalization markers, senescence markers, and immune response and redox gene products. Differences in expression, between B/AA and Caucasian patients, of RB1, hsa-let-7a, E2F1, c-MYC, TERT, and other biomolecules appear to cooperate to enhance entry into the S-phase of the cell cycle in B/AA patients. Higher expression of miR-221, an oncomiR that facilitates entry into the cell cycle S-phase, is regulated by c-MYC, which is expressed more in breast cancer samples from B/AA patients. Furthermore, the cell migration- and invasion-promoting miRNA, miR-135b, has increased relative expression in B/AA patients. Knock down of the immortalization marker TERT inhibited triple-negative breast cancer cell lines (MDA-MB-231 and MDA-MB-468) cell viability and decreased expression of TERT, MYC and WNT11. For those patients with available survival data, prognosis of stage II patients 50 years of age or younger at diagnosis, was distinctly poorer in B/AA patients. Also associated with this subset of B/AA patients are missense mutations in HUWE1 and PTEN expression loss. Relative to Caucasian non-responders to endocrine therapy, B/AA non-responders show suppressed expression of a signature gene set on which biological processes including signaling by interleukins, circadian clock, regulation of lipid metabolism by PPARα, FOXO-mediated transcription, and regulation of TP53 degradation are over-represented. Thus, we identify molecular expression patterns suggesting diminished response to oxidative stress, changes in regulation of tumor suppressors/facilitators, and enhanced immortalization in B/AA patients are likely important in defining the more aggressive molecular tumor phenotype reported in B/AA patients.

PTEN/PI3K/VEGF signaling pathway involved in the protective effect of xanthine oxidase inhibitor febuxostat against endometrial hyperplasia in rats.

Endometrial hyperplasia (EH) is a medical condition that affects many females as it increases their uterine carcinogenic potential. EH results from entangling hormonal imbalance and inflammatory response. The study examined the role of a xanthine oxidase inhibitor, febuxostat, in a rat model of EH. Adult female Wistar albino rats were subjected to estradiol valerate (EV) 2 mg/kg for 10 days to induce EH. Another group was treated concomitantly with febuxostat 10 mg/kg for the same period. The uterine malondialdehyde, reduced glutathione (GSH), and superoxide dismutase (SOD) were assessed by chemical methods. Gene expressions of phosphatidylinositol-3-kinase (PI3K), Akt, and hypoxia-inducible factor 1 alpha were assessed by the quantitative real-time polymerase chain reaction. Moreover, the vascular endothelial growth factor (VEGF) and interleukin-6 (IL-6) were measured by enzyme-linked immunosorbent assay. Histopathology and immunohistochemical techniques were used for the detection of phosphatase and tensin homolog (PTEN). The results revealed that EV administration induced complex EH with focal atypia and loss of PTEN expression by the histological examination. Uteri of the EV group showed a significant drop in GSH content and SOD activity and rise in the expressions of PI3K, Akt, VEGF, and IL-6. Febuxostat administration significantly improved the uterine GSH and SOD levels. It decreased the expressions of PI3K, Akt, VEGF, and IL-6. The endometrium showed a regression of the proliferative epithelium with the restoration of PTEN expression and the absence of the atypical features. In conclusion, febuxostat protected the endometrium against estrogen-induced EH and may be beneficial in the management along with the hormonal therapy.

Combined MEK and PI3K/p110β Inhibition as a Novel Targeted Therapy for Malignant Mesothelioma Displaying Sarcomatoid Features.

Among malignant mesotheliomas (MM), the sarcomatoid subtype is associated with higher chemoresistance and worst survival. Due to its low incidence, there has been little progress in the knowledge of the molecular mechanisms associated with sarcomatoid MM, which might help to define novel therapeutic targets. In this work, we show that loss of PTEN expression is frequent in human sarcomatoid MM and PTEN expression levels are lower in sarcomatoid MM than in the biphasic and epithelioid subtypes. Combined Pten and Trp53 deletion in mouse mesothelium led to nonepithelioid MM development. In Pten;Trp53-null mice developing MM, the Gαi2-coupled receptor subunit activated MEK/ERK and PI3K, resulting in aggressive, immune-suppressed tumors. Combined inhibition of MEK and p110β/PI3K reduced mouse tumor cell growth in vitro. Therapeutic inhibition of MEK and p110β/PI3K using selumetinib (AZD6244, ARRY-142886) and AZD8186, two drugs that are currently in clinical trials, increased the survival of Pten;Trp53-null mice without major toxicity. This drug combination effectively reduced the proliferation of primary cultures of human pleural (Pl) MM, implicating nonepithelioid histology and high vimentin, AKT1/2, and Gαi2 expression levels as predictive markers of response to combined MEK and p110β/PI3K inhibition. Our findings provide a rationale for the use of selumetinib and AZD8186 in patients with MM with sarcomatoid features. This constitutes a novel targeted therapy for a poor prognosis and frequently chemoresistant group of patients with MM, for whom therapeutic options are currently lacking. SIGNIFICANCE: Mesothelioma is highly aggressive; its sarcomatoid variants have worse prognosis. Building on a genetic mouse model, a novel combination therapy is uncovered that is relevant to human tumors.

Investigation of PTEN promoter methylation in ameloblastoma

Background Phosphatase and tensin homolog (PTEN) acts as a tumor suppressor gene. Inactivation of PTEN has been reported in various types of cancers. PTEN promoter methylation possibly underlies PTEN inactivation, which results in tumorigenesis. The aim of this study was to investigate whether PTEN promoter methylation contributes to PTEN inactivation in ameloblastoma and its associated protein expression. Material and Methods In total, 20 fresh-frozen ameloblastoma samples were evaluated for PTEN promoter methylation using methylation-specific polymerase chain reaction (MS-PCR). A subset of 10 paraffin-embedded ameloblastoma samples was examined for PTEN expression through immunohistochemistry. Four primary cultured ameloblastoma cells were investigated for PTEN promoter methylation and PTEN transcriptional expression via reverse transcription PCR. Results PTEN promoter methylation was detected in 65% (13/20) of the ameloblastoma samples. Of 10 ameloblastoma samples, 4 exhibited reduced PTEN expression. Of 5 samples with methylated PTEN, 3 (60%) were associated with loss of PTEN expression. However, PTEN expression was detected in 4 (80%) of 5 samples with unmethylated PTEN. In addition, 3 (75%) of 4 primary ameloblastoma cell cultures exhibited an inverse correlation between PTEN promoter methylation and PTEN transcription level. Conclusions PTEN promoter methylation is found in a number of ameloblastomas but not significantly correlated with loss of PTEN expression. Genetic or epigenetic mechanisms other than PTEN promoter methylation may contribute to PTEN inactivation in ameloblastoma tumor cells. Key words:PTEN, promoter methylation, ameloblastoma.

Loss of Phosphatase and Tensin Homologue (PTEN) Expression Associated with Higher Risk Grade Group Gleason Prostate Adenocarcinoma in Sanglah Hospital Denpasar

Background: Prostate cancer is the second most common malignancy in men and the fifth most common cause of death worldwide. In Asia, 59.3% of patients come for the advanced stage treatment. PTEN inactivation is identified in about 20% of primary prostate tumors in radical prostatectomy and the loss of PTEN is associated with poor clinical and pathological outcomes. The purpose of this study is to prove that there is an association between PTEN expression and risk grade group Gleason prostate adenocarcinoma in Sanglah Public Hospital, Denpasar.Methods: This is a cross-sectional study. The sample size of this study was 35 paraffin blocks. These samples were selected by proportional stratified random sampling from hematoxylin-eosin preparation. Prostate adenocarcinoma was regrouped into 3 categories based on NCCN risk stratification: low risk grade group Gleason (Gleason score ≤ 6), intermediate risk grade group Gleason (Gleason score 7), and high-risk grade group Gleason (Gleason score 8–10). Immunohistochemistry examination of PTEN was performed and the expression was evaluated by scoring method. The data were analyzed by Chi-square and logistic regression.Results: The analysis result showed that there is an association between PTEN expression and risk grade group Gleason that is statistically significant. The loss of PTEN expression associated with higher risk grade group Gleason is of the higher proportion with p=0.001; PR 3.339; 95% CI: 1.296–8.599, but there is no association between the proportion loss of PTEN expression heterogeneously or homogeneously and the risk grade group Gleason with p=0.742; PR 0.663; 95% CI: 0.179–2.457.Conclusions: This study has proved that PTEN expression is associated with higher risk grade group Gleason prostate adenocarcinoma.

Biomarkers of response and resistance to PI3K inhibitors in estrogen receptor-positive breast cancer patients and combination therapies involving PI3K inhibitors.

In this review, we discuss biomarkers of response and resistance to PI3K inhibitors (PI3Ki) in estrogen receptor-positive breast cancer, both in the early and advanced settings. We analyse data regarding PIK3CA mutations, PI3K pathway activation, PTEN expression loss, Akt signalling, insulin levels, 18FFDG-PET/CT imaging, FGFR1/2 amplification, KRAS and TP53 mutations. Most of the discussed data comprise retrospective and exploratory studies, hence many results are not conclusive. Therefore, among all of these biomarkers, only PIK3CA mutations have proved to have a predictive value for treatment with the α-selective PI3Ki alpelisib (SOLAR-1 trial) and the β-sparing PI3Ki taselisib (SANDPIPER trial) in the advanced setting. Since the accuracy of current individual biomarkers is not optimal, a composite biomarker, including DNA, RNA and protein expression data, to more precisely assess the PI3K/AKT/mTOR pathway activation status, may arise as a promising approach. Finally, we describe the rational for new combination therapies involving PI3Ki and anti-HER2 agents, chemotherapy, CDK4/6 inhibitors, mTOR inhibitors or new endocrine treatments and discuss the ongoing trials in this field.

Abstract GMM-061: MOLECULAR CHARACTERIZATION OF MOUSE MODELS OF HIGH-GRADE SEROUS CARCINOMA ARISING IN THE OVIDUCT

Abstract We recently developed genetically engineered mouse models (GEMMs) of oviductal high-grade serous carcinoma (HGSC) based on conditional inactivation of several different combinations of tumor suppressor genes (Brca1, Trp53, Rb1, and Nf1) that are recurrently mutated in human HGSCs. The histopathological features of the mouse tumors closely mimic their human tumor counterparts. In order to characterize how well the mouse tumors recapitulate the molecular characteristics of human HGSCs, targeted exome sequencing was used to analyze the 32 most commonly mutated genes in human HGSC, in 60 mouse tumors arising in the context of Brca1, Trp53, Rb1, and/or Nf1 inactivation. We employed the sequence data to assess DNA copy number alterations (CNAs) and single nucleotide variants (SNVs) in the mouse tumors. Compared to 14 normal tissues and 8 oviductal tumors arising in the context of Apc, Pten, ± Arid1a inactivation, the mouse HGSCs showed a high level of genomic instability, with many widely distributed CNAs – very similar to the widespread CNAs observed in human HGSCs. Targeted exome sequencing also showed that a subset of the mouse tumors acquired alterations observed in human HGSCs, including amplification of cMyc, and deletion of Pten. Variant analysis identified nonsynonymous SNVs in Csmd3, Crebbp, Pten, Mettl17, and Zymynd8 and a frameshift deletion of Pten. Sanger sequencing confirmed the presence of these somatic mutations in the mouse tumors and their absence in matched normal tissues. Loss of PTEN expression was observed in those tumors that acquired somatic Pten alterations. These data show that HGSCs arising in our GEMMs have very similar molecular characteristics to their human tumor counterparts. The somatic alterations are likely acquired during the relatively lengthy period (several months) between tumor initiation and progression to overt malignancy. These features render the models particularly well suited for studying the early phases of HGSC development and for translational applications aimed at identifying effective strategies for HGSC prevention and early detection. Citation Format: Yali Zhai, Yisheng Wang, Stephanie M. Schulman, Kevin Hu, Albert Liu, Scott A. Tomlins, Eric R. Fearon, and Kathleen R. Cho. MOLECULAR CHARACTERIZATION OF MOUSE MODELS OF HIGH-GRADE SEROUS CARCINOMA ARISING IN THE OVIDUCT [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr GMM-061.

INNV-41. PROSPECTIVE SELECTION OF RECURRENT GLIOBLASTOMA PATIENTS FOR TAILORED THERAPIES. RESULTS OF AN INSTITUTIONAL EXPERIENCE

Abstract INTRODUCTION Failure of clinical trials with targeted therapies in glioblastoma (GBM) is probably due to the enrollment of molecularly unselected patients. In preliminary studies, we prospectively selected recurrent GBM patients on the basis of molecular pattern and administered targeted therapy accordingly. This tailored approach gave encouraging results in term of low recurrence rate (RR) and high 6-month progression free survival (PFS-6). Here, we present the long-term results of our work. METHODS On recurrent tumor samples of 34 adult patients, we assessed the expression of VEGF and PTEN through immunohistochemistry and of EGFRvIII through RT-PCR. Patients with VEGF overexpression were treated with bevacizumab (10 mg/Kg i.v. every 2 weeks in 6-week cycles). Patients with EGFRvIII expression and normal PTEN expression added erlotinib (150 mg/day orally). Patients with loss of PTEN expression, irrespective of EGFRvIII status, added sirolimus (1–10 mg/day orally). RESULTS Sixteen patients received bevacizumab alone (bev), 14 bevacizumab plus erlotinib (bev+erl) and 4 bevacizumab plus sirolimus (bev+sir). RR was 50% in the whole cohort and 37.5%, 57.1% and 75% in bev, bev+erl and bev+sir groups, respectively. PFS-6 was 55.9% in the whole cohort and 50%, 64.3% and 50% in bev, bev+erl and bev+sir groups, respectively. Our data compare favorably with those from the large EORTC 26101 trial, which showed a RR of 41.5% and a PFS-6 lower than 30%. When considering sustained response (defined as PFS ≥ 12 months), we overall observed a 20.6% rate, with the highest value in bev+erl subgroup (28.6%). Interestingly, in EORTC 26101 trial, less than 10% of patients achieved PFS ≥ 12 months. CONCLUSIONS Our results confirm that the tailored approach in recurrent GBM provides an advantage in terms of RR, PFS and, above all, of long-term responses, compared with trials without molecular selection.

PTEN Alterations as a Potential Mechanism for Tumor Cell Escape from PD-1/PD-L1 Inhibition

The recent approval of immune checkpoint inhibitors drastically changed the standard treatments in many advanced cancer patients, but molecular changes within the tumor can prevent the activity of immunotherapy drugs. Thus, the introduction of the inhibitors of the immune checkpoint programmed death-1/programmed death ligand-1 (PD-1/PD-L1), should prompt deeper studies on resistance mechanisms, which can be caused by oncogenic mutations detected in cancer cells. PTEN, a tumor suppressor gene, dephosphorylates the lipid signaling intermediate PIP3 with inhibition of AKT activity, one of the main effectors of the PI3K signaling axis. As a consequence of genetic or epigenetic aberrations, PTEN expression is often altered, with increased activation of PI3K axis. Interestingly, some data confirmed that loss of PTEN expression modified the pattern of cytokine secretion creating an immune-suppressive microenvironment with increase of immune cell populations that can promote tumor progression. Moreover, PTEN loss may be ascribed to reduction of tumor infiltrating lymphocytes (TILs), which can explain the absence of activity of immune checkpoint inhibitors. This review describes the role of PTEN loss as a mechanism responsible for resistance to anti PD-1/PD-L1 treatment. Moreover, combinatorial strategies between PD-1/PD-L1 inhibitors and PI3K/AKT targeting drugs are proposed as a new strategy to overcome resistance to immune checkpoint inhibition.

The evolving role of cytoreductive nephrectomy: incorporating genomics of metastatic renal cell carcinoma into treatment decisions.

Recent publications evaluating cytoreductive nephrectomy in the era of targeted therapy emphasize the importance of patient selection. We reviewed the predictive role of genetic alterations in patients with metastatic renal cell carcinoma (mRCC) undergoing cytoreductive nephrectomy. Studies evaluating the association between genetic alterations and outcomes following systemic treatment for mRCC include mainly patients after cytoreductive nephrectomy. Expression of proangiogenic genes, single nucleotide polymorphisms involving genes of the vascular-endothelial growth factor (VEGF) pathway and somatic mutations of chromatin remodeling genes were associated with response to VEGF-targeted therapy. Outcomes following treatment with mammalian target of rapamycin (mTOR) inhibitors were initially associated with mTOR/TSC1/TSC2 mutations; however, subsequent studies did not validate these findings but rather found an association between loss of PTEN expression and PBRM1 mutations and improved outcomes. Loss of PBRM1 was initially linked to response to immunotherapy; however, larger studies question this association and showed high expression of T-effector gene signature predicted improved outcome. Primary tumors with low intratumor heterogeneity but elevated somatic copy-number alterations were associated with rapid progression at multiple sites. Genetic alterations may help select patients for cytoreductive nephrectomy and optimize timing of treatment. Intratumor heterogeneity and genetic discordance between primary and metastatic tumors may limit clinical applicability. Future studies should evaluate approaches to overcome these limitations.

Loss of PTEN Accelerates NKX3.1 Degradation to Promote Prostate Cancer Progression.

NKX3.1 is the most commonly deleted gene in prostate cancer and a gatekeeper suppressor. NKX3.1 is a growth suppressor, mediator of apoptosis, inducer of antioxidants, and enhancer of DNA repair. PTEN is a ubiquitous tumor suppressor that is often decreased in prostate cancer during tumor progression. Steady-state turnover of NKX3.1 is mediated by DYRK1B phosphorylation at NKX3.1 serine 185 that leads to polyubiquitination and proteasomal degradation. In this study, we show PTEN is an NKX3.1 phosphatase that protects NKX3.1 from degradation. PTEN specifically opposed phosphorylation at NKX3.1(S185) and prolonged NKX3.1 half-life. PTEN and NKX3.1 interacted primarily in the nucleus as loss of PTEN nuclear localization abrogated its ability to bind to and protect NKX3.1 from degradation. The effect of PTEN on NKX3.1 was mediated via rapid enzyme-substrate interaction. An effect of PTEN on Nkx3.1 gene transcription was seen in vitro, but not in vivo. In gene-targeted mice, Nkx3.1 expression significantly diminished shortly after loss of Pten expression in the prostate. Nkx3.1 loss primarily increased prostate epithelial cell proliferation in vivo. In these mice, Nkx3.1 mRNA was not affected by Pten expression. Thus, the prostate cancer suppressors PTEN and NKX3.1 interact and loss of PTEN is responsible, at least in part, for progressive loss of NKX3.1 that occurs during tumor progression. SIGNIFICANCE: PTEN functions as a phosphatase of NKX3.1, a gatekeeper suppressor of prostate cancer.

Endometriosis-assEndometriosis-associated ovarian tumors: morphological and immunohistochemical features

Background. In 2016, the World Health Organization published an updated version of the Histological Classification for ovarian tumors presenting a new category of endometriosis-associated tumors. The predictors of malignant transformation of endometriosis have not been clearly defined so far.Purpose. The search for histological and immunohistochemical markers of endometriosis-associated malignancy.Materials and methods. 28 female patients with endometrioid ovarian cancer and 11 patients with clear cell ovarian carcinoma were enrolled. Histological and immunohistochemical studies were carried out using conventional techniques. Immunohistochemistry was applied to determine the hormone receptor status: expression of steroid hormone receptors, BAF250a (ARID1A), PTEN, P-catenin, MSH6, PMS2, р-53, WT-1, proliferative index (Ki-67). Microsatellite instability (MSI) testing was conducted according to the standard protocol.Results. In all cases of ovarian cancer, histological examination showed one of the endometriosis features. Atypical endometriosis was found in 39 % (11 / 28) of endometrioid tumors and in 9% (1/ 11) of clear cell carcinomas. Endometrioid ovarian cancer was found to be ER (74±7,8%) — and PR (67±5,4%) — positive; Ki-67 index was 68,2±3,7 %; loss of BAF250a (ARID1A) expression was observed in 14% (4/ 28), loss of PTEN expression in 29 % (8 / 28), nuclear expression of P-catenin in 32% (9/28) of cases. Loss of MMR expression was detected in 7% (2/28) of cases. MSI was found in one case only, which was also associated with loss of expression of BAF250a (ARID1A) and MSH6. Clear cell carcinoma of the ovary showed histological criteria for endometriosis; however, there were no changes immunohistochemical markers expression that were typical for endometriosis-associated malignancies. It could be due to a small number of patients in the group so further research is needed.Conclusion. Atypical endometriosis may be a morphological precursor of endometrioid and clear cell carcinoma of the ovary. Comprehensive assessment of a marker panel consisting of BAF250a (ARID1A), P-catenin, PTEN, p53, Ki-67 index, PMS2 and MSH6 will allow improving the diagnosis of atypical endometriosis and endometriosis-associated ovarian cancer.

Immunohistochemical expression of mismatch repair proteins (MSH2, MSH6, MLH1, and PMS2) in prostate cancer: correlation with grade groups (WHO 2016) and ERG and PTEN status.

The role of DNA MMR genes in prostate cancer (PrCa) is controversial, as genetic alterations leading to microsatellite instability are incompletely defined in these tumors. ERG rearrangements and PTEN loss are concomitant events in PrCa. The aim of this study has been to analyze the immunohistochemical (IHC) expression of MSH2, MSH6, MLH1, PMS2, ERG, and PTEN and their potential association with the grade group (GG) grading system (WHO 2016) and PSA recurrence in a series of 200 PrCa (PSMAR-Biobank, Barcelona, Spain). MSH2, MLH1, PMS2, and PTEN losses were documented in 8%, 5%, 2%, and 36.5%, respectively. ERG expression was found in 48%. MSH6 showed an increase of expression with respect to basal levels in 42.1% of the cases. A statistical association between MSH6 overexpression and GG5 was found (p = 0.0281). ERG-wild-type cases were associated with single MSH2 loss (p = 0.024), and MSH2 and/or MLH1 loss (p = 0.019). The percentage of cases with PTEN loss was 20.5% (8/39) in GG1, 37.6% (53/141) of clustered GG2 to 4, and 60% (12/20) of GG5 (chi-square test, p = 0.01). Thus, PTEN expression loss was statistically more frequent in the upper-grade tumors. PMS2 loss was an infrequent event, but it was statistically associated with shorter time to PSA recurrence (p = 0.011). These results suggest the existence of an alternative non-ERG pathway associated with MSH2 or MLH1 expression loss. MSH6 overexpression could be a marker of aggressiveness in PrCa. The IHC assessment of DNA MMR proteins, ERG and PTEN, could identify different altered PrCa pathways, which could aid patient stratification.

PI3K inhibition enhances the anti-tumor effect of eribulin in triple negative breast cancer

Loss of the tumor suppressor phosphatase and tensin homolog (PTEN) is commonly observed in triple negative breast cancer (TNBC), leading to activation of the phosphoinositide 3-kinase (PI3K) signaling to promote tumor cell growth and chemotherapy resistance. In this study, we investigated whether adding a pan-PI3K inhibitor could improve the cytotoxic effect of eribulin, a non-taxane microtubule inhibitor, in TNBC patient-derived xenograft models (PDX) with loss of PTEN, and the underlying molecular mechanisms. Three TNBC-PDX models (WHIM6, WHIM12 and WHIM21), all with loss of PTEN expression, were tested for their response to BKM120 and eribulin, alone or in combination in vivo. In addition, the effect of drug treatment on cell proliferation and cell cycle progression were also performed in vitro using a panel of TNBC cell lines, including 2 derived from PDX models. The combination of eribulin and BKM120 led to additive or synergistic anti-tumor effect in 2 of the 3 PDX models, accompanied by an enhanced mitotic arrest and apoptosis in sensitive PDX models. In addition, the combination was synergistic in reducing mammosphere formation, and markers for epithelial-mesenchymal transition (EMT). In conclusion, PI3K inhibition induces synergistic anti-tumor effect when combined with eribulin, by enhancing mitotic arrest and apoptosis, as well as, reducing the cancer stem cell population. This study provides a preclinical rationale to investigate the therapeutic potential for the combination of PI3K inhibition and eribulin in the difficult to treat TNBC. Further studies are needed to identify the biomarkers of response for target patient selection.

Combined loss of TFF3 and PTEN is associated with lethal outcome and overall survival in men with prostate cancer.

Trefoil Factor 3 (TFF3) has been implicated in Prostate Cancer (PCa) progression. However, its prognostic value and association with other biomarkers have not been fully explored. We assessed the combined value of TFF3 and PTEN in two cohorts: one is managed surgically for localized PCa and the second is managed non-surgically by androgen deprivation therapy for advanced disease. 228 radical prostatectomies (RP) and 318 transurethral resection of prostate (TURP) samples were assessed by immunohistochemistry (IHC) for TFF3 and by IHC and fluorescent in situ hybridization (FISH) for PTEN. Results of biomarkers expression were correlated with various pathological and clinical outcome parameters including biochemical recurrence (BCR) in the RP cohort and cancer-specific mortality (PCSM) and overall survival (OS) in the TURP cohort. TFF3 expression was detected in 131/226 (57.9%) RP samples and 148/318 (46.5%) of TURP cases. In general, TFF3 positivity was less frequently observed with advanced Gleason Groups. TFF3 expression was also assessed in relation to PTEN expression. Only 15-16% of TFF3-expressed cases were present in association with complete loss of PTEN expression in the TURP and localized cohorts, respectively. Loss of TFF3 expression was not related to BCR after RP, but was prognostic in the non-surgical cohort and associated with decrease OS and PCSM (HR 2.31, CI: 1.67-3.18, p < 0.0001) and (HR 3.99, CI: 2.43-6.56; p < 0.0001), respectively. Adjusting for Gleason score, combined loss of TFF3/PTEN was most associated with OS (HR 2.33, CI: 1.49-3.62; p < 0.0001) and PCSM (HR = 3.44, CI: 1.75-6.78, p < 0.0001). The study documents for the first time significant association for combined status of TFF3 expression and PTEN loss in OS and PCSM in patients not managed by surgical intervention. Prospective assessment of PTEN and TFF3 may provide further insight into molecularly subtyping PCa and aid in stratifying patients at risk for lethal disease.

Differential response to neoadjuvant hormonal therapy in prostate cancer: Predictive morphological parameters and molecular markers.

The predictive value of the histological parameters and molecular markers for neoadjuvant hormonal therapy (NHT) in prostate cancer (PCa) has not been well established. The aim of this study is to determine pathological variables that can predict differences in response to NHT in PCa. A total of 85 locally high risk PCa patients with matched preoperative needle biopsies and radical prostatectomy (RP) specimens were included. All patients were treated with NHT for at least 3 months. We quantified the response to NHT using a new proposed pathological grading system. The system classified tumors into five groups (grades 0-4) according to the severity of histological response. We then categorized the PCa patients into drug-sensitive (DS) group (Grades 2-4) and drug-resistant (DR) group (Grades 0-1). Two pathologists assessed each pretreated tumors for presence or absence of nine morphological features. The expression of androgen receptor (AR), ERG, and PTEN were evaluated by immunohistochemistry (IHC) as well. Statistical analysis was performed to identify significant associations between differentially histological response to NHT and morphological features as well as molecular aberrations. We evaluated different prediction models using receiver operating characteristic (ROC) curves and area under the ROC curve (AUC) analysis. 73% (n = 62/85) of tumors in our cohort belonged to DS group, whereas 27% (n = 23/85) of tumors were DR. Univariate logistic analysis suggested four pathological variables, cribriform growth pattern, macronucleoli, ductal adenocarcinoma differentiation, and PTEN loss in needle biopsies were significantly associated with DR effect, all with P-value < 0.05. Multivariate logistic regression analysis revealed that the three parameters as significant predictive factors for predicting DR effect. These were macronucleoli (RR = 4.008, P = 0.002), ductal adenocarcinoma differentiation (RR = 11.659, P = 0.009) and PTEN loss expression (RR = 7.275, P = 0.015). The AUC of three integrated indicators model was 0.781. Our study suggested that the presence of tumor cribriform growth pattern, macronucleoli, ductal adenocarcinoma differentiation, and PTEN loss in needle biopsies are of value in predicting tumor response to NHT regimen. Multivariate logistic regression analysis revealed the performance of combined pathological indicators in predicting DR response was better than that of model based on individual factor alone.