A comprehensive immunohistochemical and molecular approach to the PI3K/AKT/mTOR (phosphoinositide 3-kinase/v-akt murine thymoma viral oncogene/mammalian target of rapamycin) pathway in bladder urothelial carcinoma

Familial CCM Genes Might Not Be Main Drivers for Pathogenesis of Sporadic CCMs-Genetic Similarity between Cancers and Vascular Malformations

Cerebral cavernous malformations (CCMs) are abnormally dilated intracranial capillaries that form cerebrovascular lesions with a high risk of hemorrhagic stroke. Recently, several somatic "activating" gain-of-function (GOF) point mutations in PIK3CA (phosphatidylinositol-4, 5-bisphosphate 3-kinase catalytic subunit p110α) were discovered as a dominant mutation in the lesions of sporadic forms of cerebral cavernous malformation (sCCM), raising the possibility that CCMs, like other types of vascular malformations, fall in the PIK3CA-related overgrowth spectrum (PROS). However, this possibility has been challenged with different interpretations. In this review, we will continue our efforts to expound the phenomenon of the coexistence of gain-of-function (GOF) point mutations in the PIK3CA gene and loss-of-function (LOF) mutations in CCM genes in the CCM lesions of sCCM and try to delineate the relationship between mutagenic events with CCM lesions in a temporospatial manner. Since GOF PIK3CA point mutations have been well studied in reproductive cancers, especially breast cancer as a driver oncogene, we will perform a comparative meta-analysis for GOF PIK3CA point mutations in an attempt to demonstrate the genetic similarities shared by both cancers and vascular anomalies.

2,5-Hexanedione Affects Ovarian Granulosa Cells in Swine by Regulating the CDKN1A Gene: A Transcriptome Analysis

N-hexane, a common industrial organic solvent, causes multiple organ damage owing to its metabolite, 2,5-hexanedione (2,5-HD). To identify and evaluate the effects of 2,5-HD on sows’ reproductive performance, we used porcine ovarian granulosa cells (pGCs) as a vehicle and carried out cell morphology and transcriptome analyses. 2,5-HD has the potential to inhibit the proliferation of pGCs and induce morphological changes and apoptosis depending on the dose. RNA-seq analyses identified 4817 differentially expressed genes (DEGs), with 2394 down-regulated and 2423 up-regulated following 2,5-HD exposure treatment. The DEG, cyclin-dependent kinase inhibitor 1A (CDKN1A), according to the Kyoto Encyclopedia of Genes and Genomes enrichment analysis, was significantly enriched in the p53 signaling pathway. Thus, we evaluated its function in pGC apoptosis in vitro. Then, we knocked down the CDKN1A gene in the pGCs to identify its effects on pGCs. Its knockdown decreased pGC apoptosis, with significantly fewer cells in the G1 phase (p < 0.05) and very significantly more cells in the S phase (p < 0.01). Herein, we revealed novel candidate genes that influence pGCs apoptosis and cell cycle and provided new insights into the role of CDKN1A in pGCs during apoptosis and cell cycle arrest.

Identification of immuno-infiltrating MAP1A as a prognosis-related biomarker for bladder cancer and its ceRNA network construction

BACKGROUNDS

Approximately 75% of bladder cancer occurrences are of the non-muscle-invasive type. The estimated five-year survival rate is 26%-55%. Currently, there is no reliable biomarker available for early diagnosis and prognosis of bladder cancer. The present study aims to identify a biomarker using bioinformatic approaches to provide a new insight in clinical research for early diagnosis and prognosis of bladder cancer.

METHODS

Clinical data and a transcriptome of bladder cancer were obtained from TCGA, GEO, GETx, and UCSC Xena. The differential expressed gene (DEG) analysis, weighted gene co-expression network analysis (WGCNA), and survival analysis using the Kaplan-Meier and Cox proportional-hazards models were used to identify the Microtubule-associated Proteins 1A (MAP1A). on overall survival (OS) and disease-free survival (DFS) was analyzed using GEPIA and GETx databases. The TIMER 2.0 database predicted the correlation between MAP1A and immunocytes and immune checkpoints. Target prediction of the regulated competing endogenous RNAs (ceRNAs) network of MAP1A was performed using starBase and TargetScan. Cystoscope v3.7.2 software was used to visualize the ceRNA coexpression network. The R programming language v4.0.2 was applied as an analytic tool. Gene expression of MAP1A verified by RT-qPCR.

RESULTS

The low expression of MAP1A was verified in bladder cancer tissues and bladder cancer cell lines SW780 and 5637. P < 0.001 were obtained by Kaplan-Meier survival analysis and Cox proportional hazards model, with a hazard ratio (HR) of 1.4. Significant correlations between MAP1A and OS (P < 0.001, HR = 1.9) as well as DFS (P < 0.05, HR = 1.7) in bladder cancer were identified through gene expression profiling interactive analysis (GEPIA), indicating MAP1A may be a high-risk factor. Significant correlation in single copy-number variation of MAP1A gene with CD8⁺ T cells, and myeloid dendritic cells (MDCs) (P < 0.05) was noted. MAP1A expression was shown to be significantly correlated with the amount of CD4⁺ T cells and CD8⁺ T cells, MDCs, macrophages, and neutrophils in a statistically significant positive manner (P < 0.001). However, the MAP1A expression demonstrated a strong negative connection with B cells (P < 0.001). Except for macrophage M1 genes IRF5 and PTGS2, MAP1A expression was significantly correlated with the gene levels in immunocytes such as CD4⁺ T cells, CD8⁺ T cells, B cells, dendritic cells (DCs), macrophages, and neutrophils (Cor > 0.2, P < 0.001), as well as immune checkpoint related genes including cytotoxic t-lymphocyte-associated protein 4 (CTLA-4), programmed death 1 (PD-1), programmed death ligand 1 (PD-L1) (P < 0.001). Finally, we predicted that the MAP1A-interacting miRNA was miR-34a-5p, and the MAP1A endogenous competing RNAs were LNC00667, circ_MAP1B, and circ_MYLK, respectively. These findings support the need for further studies on the mechanism underlying the pathogenesis of this disease.

CONCLUSION

MAP1A is considered as a prospective biomarker for early diagnosis, therapeutic observation, and prognosis analysis in bladder cancer.

NF2 Alteration/22q Loss Is Associated with Recurrence in WHO Grade 1 Sphenoid Wing Meningiomas

Sphenoid wing meningiomas account for 11−20% of all intracranial meningiomas and have a higher recurrence rate than those at other sites. Recent molecular biological analyses of meningiomas have proposed new subgroups; however, the correlation between genetic background and recurrence in sphenoid wing meningiomas has not yet been fully elucidated. In this study, we evaluated the clinical characteristics, pathological diagnosis, and molecular background of 47 patients with sphenoid wing meningiomas. Variants of NF2, AKT1, KLF4, SMO, POLR2A, PIK3CA, TRAF7, and TERT were determined using Sanger sequencing, and 22q loss was detected using multiplex ligation-dependent probe amplification. Alterations were localized at NF2 in 11 cases, had other genotypes in 17 cases, and were not detected in 12 cases. Interestingly, WHO grade 1 meningiomas with NF2 alteration/22q loss (p = 0.008) and a MIB-1 labeling index > 4 (p = 0.03) were associated with a significantly shorter recurrence-free survival, and multivariate analysis revealed that NF2 alteration/22q loss was associated with recurrence (hazard ratio, 13.1). The duration of recurrence was significantly shorter for meningiomas with NF2 alteration/22q loss (p = 0.0007) even if gross-total resection was achieved. Together, these findings suggest that NF2 alteration/22q loss is associated with recurrence in WHO grade 1 sphenoid wing meningiomas.

Associations of Genetic Polymorphisms of mTOR rs2295080 T/G and rs1883965 G/A with Susceptibility of Urinary System Cancers

Background. Genetic polymorphisms in mammalian target of rapamycin (mTOR) signaling axis can influence the susceptibility of cancer. The relationship between mTOR gene variants rs2295080 T/G and rs1883965 G/A and the risk of cancer remains inconsistent. The present study is aimed at comprehensively investigating the association between mTOR polymorphisms and susceptibility to cancer. Methods. We conducted a comprehensive assessment using odds ratios (ORs), corresponding 95% confidence intervals (CIs), and in silico tools to evaluate the effect of mTOR variations. Immunohistochemical staining (IHS) and GSEA analysis were used to investigate the expression of mTOR in urinary system cancer. Results. The pooled analysis involved 22 case-control studies including 14,747 cancer patients and 16,399 controls. The rs2295080 T/G polymorphism was associated with the risk of cancer (G-allele versus T-allele, $\text{OR}=0.89$ , $95\%\text{CI}=0.80$ –0.98, $P=0.023$ ; GT versus TT, $\text{OR}=0.88$ , $95\%\text{CI}=0.81$ –0.96, $P=0.004$ ; GG+GT versus TT, $\text{OR}=0.87$ , $95\%\text{CI}=0.78$ –0.96, $P=0.008$ ), especially for cancers of the urinary system, breast, and blood. Variation rs1883965 G/A was associated with cancer susceptibility, especially for digestive cancer. IHS analysis showed that mTOR was upregulated in prostate and bladder cancer. GSEA revealed that the insulin signaling pathway, lysine degradation pathway, and mTOR signaling pathway were enriched in the high mTOR expression group. Conclusions. The mTOR rs2295080 T/G polymorphism may be associated with susceptibility of urinary cancer. The expression of mTOR is positively correlated with tumor malignancy in prostate cancer.

Correlation of the AKT/mTOR signaling pathway with the clinicopathological features and prognosis of nasopharyngeal carcinoma

The primary aim of this study was to examine the correlation of the AKT/mTOR signaling pathway with the clinicopathological features and prognostic significance in nasopharyngeal carcinoma (NPC). The study tissues were collected from 285 patients with NPC and normal mucosal tissues were obtained from 289 individuals with normal nasopharynxes. Immunohistochemical staining was used to detected the expression of the AKT, mTOR, and p70 ribosomal S6 kinase (P70S6K) proteins. Follow-up was performed for between 8 and 60 months. Spearman’s rank correlation analysis was performed to evaluate the correlation of the expression of the AKT, mTOR, and P70S6K proteins in NPC tissues. Kaplan-Meier curves were plotted to show the survival of patients with NPC. A Cox proportional hazards model was used to explore the independent risk factors for prognosis. The expression of the AKT, mTOR, and P70S6K proteins in NPC tissues was higher than that in healthy nasopharyngeal mucosal tissues, and was correlated with T-staging, N-staging, clinical stage, distant metastasis, and differentiation. The positive expression of the AKT, mTOR, and P70S6K proteins was higher in patients with stage III/IV NPC, low differentiation, and metastasis. The survival rates of patients with NPC with AKT-positive, mTOR-positive, and P70S6K-positive expression were considerably lower than those without the expression of these proteins. Distant metastasis and the overexpression of the AKT, mTOR, and P70S6K proteins were independent risk factors for the prognosis of patients with NPC. The results obtained from this study indicated an association between the AKT/mTOR signaling pathway and the progression of NPC. The upregulation of the AKT/mTOR pathway in patients with NPC is a predictor of poor prognosis.

Prognostic Role of the Activated p-AKT Molecule in Various Hematologic Malignancies and Solid Tumors: A Meta-Analysis

Cancer is one of the main causes of human death worldwide. Recently, many studies have firmly established the causal relationship between oxidative stress and cancer initiation and progression. As a key protein in PI3K/Akt signaling pathway, p-AKT (phosphorylated Akt) participates in the process of oxidative stress and plays a prognostic role in various hematologic tumors and solid tumors. We conducted a comprehensive search of the PubMed, Embase and Cochrane libraries to identify studies published in the past decade involving cancer patients expressing p-AKT that reported overall survival (OS) during follow-up. In this study, 6,128 patients in total were evaluated from 29 enrolled articles, and we concluded that overexpression of p-AKT was closely related to worse OS in cancer patients with a hazard ratio (HR) of 2.33 (95% CI: 1.67–4.00). Furthermore, we conducted a subgroup analysis, and the results indicated that overexpression of p-AKT was associated with worse OS in hematological tumor (HR: 1.64, 95% CI: 1.41–1.92), and solid tumor (HR: 2.44, 95% CI: 1.61–5.26). High expression of p-AKT is related to poor prognosis of various hematologic tumors and solid tumors.

Effect and mechanism of PI3K/AKT/mTOR signaling pathway in the apoptosis of GC-1 cells induced by nickel nanoparticles

Nickel nanoparticles (Ni NPs) have a wide range of application prospects, but there is still a lack of their safety evaluation for the reproductive system. Nowadays, male reproductive health has been widely concerned because of the increasing incidence of male infertility. Studies have shown that Ni NPs can cause male reproductive toxicity. The purpose of this study was to investigate the toxicity of Ni NPs on GC-1 cells, a mouse spermatogonia cell line, and to explore the possible mechanism underlying the induction of apoptosis via PI3K/AKT/mTOR signaling pathway. The cell ultrastructure was firstly observed under a transmission electron microscope. Then, cell proliferation, cycle and apoptosis were detected by CCK-8 and flow cytometry, respectively. Furthermore, the expression levels of related proteins and genes were determined by Western blot and Reverse transcription-polymerase chain reaction, respectively. The results showed that Ni NPs could not only cause changes in cell ultrastructure, decreased survival rate and arrested G1 phase cell cycle, but also activated apoptosis pathway by inhibiting the PI3K/AKT/mTOR signaling pathway. The results of this study provide novel insights to explore the mechanisms of reproductive toxicity of Ni NPs and are of great significance to develop safety evaluation criteria for Ni NPs.

Cytokine-Mediated Dysregulation of Signaling Pathways in the Pathogenesis of Multiple Myeloma

Multiple myeloma (MM) is a hematologic disorder of B lymphocytes characterized by the accumulation of malignant plasma cells (PCs) in the bone marrow. The altered plasma cells overproduce abnormal monoclonal immunoglobulins and also stimulate osteoclasts. The host’s immune system and microenvironment are of paramount importance in the growth of PCs and, thus, in the pathogenesis of the disease. The interaction of MM cells with the bone marrow (BM) microenvironment through soluble factors and cell adhesion molecules causes pathogenesis of the disease through activation of multiple signaling pathways, including NF-κβ, PI3K/AKT and JAK/STAT. These activated pathways play a critical role in the inhibition of apoptosis, sustained proliferation, survival and migration of MM cells. Besides, these pathways also participate in developing resistance against the chemotherapeutic drugs in MM. The imbalance between inflammatory and anti-inflammatory cytokines in MM leads to an increased level of pro-inflammatory cytokines, which in turn play a significant role in dysregulation of signaling pathways and proliferation of MM cells; however, the association appears to be inadequate and needs more research. In this review, we are highlighting the recent findings on the roles of various cytokines and growth factors in the pathogenesis of MM and the potential therapeutic utility of aberrantly activated signaling pathways to manage the MM disease.

The function and mechanism of circular RNAs in gastrointestinal tumours

Gastrointestinal tumours are tumours that originate in the digestive tract and have extremely high morbidity and mortality. The main categories include: oesophageal, gastric, and colorectal cancers. Circular RNAs are a new class of non‐coding RNAs with a covalent closed‐loop structure without a 5’ cap or a 3’ poly A tail, which can encode a small amount of polypeptide. Recent studies have shown that circRNAs are involved in multiple biological processes during the development of gastrointestinal tumours including proliferation, invasion and metastasis, radio‐ and chemoresistance, and inflammatory responses. Also, the clinical and pathological characteristics of the patient, such as staging and lymph node metastasis, are closely associated with the expression level of circRNAs. Further investigation of the function and the role of circRNAs in the development of gastrointestinal tumours will provide new directions for its clinical diagnosis and treatment.

The Esophageal Cancer and the PI3K/AKT/mTOR Signaling Regulatory microRNAs: a Novel Marker for Prognosis, and a Possible Target for Immunotherapy

The Phosphatidylinositol 3-kinase/AKT/Mammalian Target of Rapamycin (PI3K/AKT/mTOR) pathway has a critical regulatory role in cell biology including translation, transcription, and autophagy. Dysregulation of this pathway is involved in the pathogenesis, development, and prognosis of esophageal cancer that has been assessed in the recent years and its potential as a target in therapy. This report summarizes the current knowledge about PI3K/AKT/mTOR pathway and its cross-talk with a focus on the value of targeting this pathway as a potential therapeutic target in the treatment of esophageal cancer.

Mutations in gliclazide-associated genes may predict poor bladder cancer prognosis

In recent years, an increasing number of patients have had diabetes and cancer simultaneously; thus, it is crucial for physicians to select hypoglycemic drugs with the lowest risk of inducing cancer. Gliclazide is a widely used sulfonylurea hypoglycemic drug, but its cancer risk remains controversial. Here, we explored the primary targets of gliclazide and its associated genes by querying an available database to construct a biological network. By using DrugBank and STRING, we found two primary targets of gliclazide and 50 gliclazide-associated genes, which were then enrolled for Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis using WebGestalt. From this analysis, we obtained the top 15 KEGG pathways. Accurate analysis of these KEGG pathways revealed that two pathways, one linked to bladder cancer and the other linked to the phosphoinositide 3-kinase-AKT signaling pathway, are functionally associated with gliclazide, and from these we identified four overlapping genes. Finally, genomic analysis using cBioPortal showed that genomic alterations of these four overlapping genes predict poor prognosis for patients with bladder cancer. In conclusion, gliclazide should be used with caution as a hypoglycemic drug for diabetic patients with cancer, especially bladder cancer. In addition, this study provides a functional network analysis to flexibly explore drug interaction systems and estimate their safety.

MAN1B1 is associated with poor prognosis and modulates proliferation and apoptosis in bladder cancer

Bladder cancer (BC) has been regarded as the most common malignancy of the urinary system worldwide. With lack of investigations for molecular pathogenesis underlying that develop BC, the therapeutic efficacy of several therapeutic approaches existing is still unsatisfactory. Here, our study aimed to explore the potentially biological function of MAN1B1 on BC. In this study, MAN1B1 expression level in BC tissues and normal tissues was analyzed based on The Cancer Genome Atlas (TCGA) data and correlation between its expression and prognosis was determined using Kaplan-Meier analysis. Knockout of MAN1B1 was performed using silencing RNA and the efficacy of MAN1B1 knockout was identified using quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis. The BC cells proliferation was assessed by Cell Counting Kit-8 (CCK8) assay, and then the cells apoptosis was detected by Annexin V-fluorescein isothiocyanate (Annexin V-FITC)/propidium iodide (PI) staining and flow cytometry following MAN1B1 knocked down by small interfering RNA. Protein kinase B (AKT) signaling was evaluated by detecting related markers, namely AKT, p-AKT, 4E-BP-1 and Bax using western blot assay. As a result, the MAN1B1 expression was higher in BC tissues than those in normal tissues, besides, its overexpression was associated with poor prognosis. Moreover, MAN1B1 reduction by silencing RNA approach resulted in BC cells proliferation suppression and BC cells apoptosis promotion. Finally, AKT signaling activity was inhibited by MAN1B1 silencing. Taken together, these results unraveled that MAN1B1 may act on an oncogenic action in BC, which improved the likelihood of MAN1B1 taking on a promising prognostic biomarker and a potential target for treating BC.

Analysis of the PI3K-AKT-mTOR pathway in penile cancer: evaluation of a therapeutically targetable pathway

Objectives

To determine whether phosphatidylinositol-4,5-bisphosphate 3- kinase, catalytic subunit alpha (PIK3CA) copy number gain is common and could prove a useful marker for the activation status of the PI3K-AKT-mTOR pathway in penile squamous cell carcinoma (PSCC).

Methods

Fresh frozen tissue and archival blocks were collected from 24 PSCC patients with 15 matched normal penile epithelium (NPE) tissue from St George’s Hospital. PIK3CA mutational and copy number status (CNS) was assessed via Sanger sequencing and fluorescence in-situ hybridisation, respectively. PIK3CA RNA expression was quantified using TaqMan gene expression assay. HPV DNA was detected with INNO-LiPA assay. p-AKT and p-mTOR protein expression were assessed using western blot and immunohistochemistry.

Results

PIK3CA copy number gain was found in 11/23 (48%) patients, with mutations present in only 2/24 (8%) patients. In comparison to NPE, PSCC showed significantly lower PIK3CA RNA expression (p=0.0007), p-AKT (Ser473) nuclear immunoexpression (p=0.026) and protein expression of p-AKT (Thr308) (p=0.0247) and p-mTOR (Ser2448) (p=0.0041). No association was found between PIK3CA CNS and p-AKT and p-mTOR protein expression.

Conclusion

Based on our results the PI3K-AKT-mTOR pathway is not a key driver in PSCC carcinogenesis and the therapeutic targeting of this pathway is unlikely to produce significant clinical benefit.

Association between single nucleotide polymorphisms in the PI3K/AKT/mTOR pathway and bladder cancer risk in a sample of Iranian population

In the past few years several investigations have focused on the role of PI3K/AKT/mTOR pathway and its deregulations in different cancers. This study aimed to examine genetic polymorphisms of this pathway in bladder cancer (BC). In this case-control study, 235 patients with pathologically confirmed bladder cancer and 254 control subjects were examined. PIK3CA, AKT1 and mTOR variants were analyzed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The findings proposed that the PIK3CA rs6443624 SNP significantly decreased the risk of BC (OR=0.44, 95 % CI=0.30-0.65, p<0.0001 CA vs CC; OR=0.35, 95 % CI=0.16-0.78, p=0.0107, AA vs CC; OR=0.60, 95 % CI=0.46-0.79, p=0.0002, A vs T). The AKT1 rs2498801 variant is associated with a decreased risk of BC (OR=0.57, 95 % CI=0.39-0.82, p=0.003, AG vs AA; OR=0.74, 95 % CI=0.56-0.97, p=0.032, G vs A) while, AKT1 rs1130233 polymorphism considerably increased the risk of BC (OR=3.70, 95 % CI=2.52-5.43, p<0.0001, GA vs GG; OR=5.81, 95 % CI=1.53-21.97, p=0.010, AA vs GG; OR=2.71, 95 % CI=1.98-3.70, p<0.0001, A vs G). Additionally, mTOR rs2295080 variant notably increased the risk of BC (OR=2.25, 95 % CI=1.50-3.38, p<0.0001, GT vs GG; OR=4.75, 95 % CI=2.80-8.06, p<0.0001, TT vs GG; OR=3.10, 95 % CI=2.34-4.10, p<0.0001, T vs G). None of the other examined polymorphisms (AKT1 rs1130214, AKT1 rs3730358, mTOR rs1883965) revealed significant association with BC. In conclusion, our findings suggest that PIK3CA rs6443624, AKT1 rs2498801, AKT1 rs1130233, as well mTOR rs2295080 polymorphism may be related to bladder cancer development in a sample of Iranian population. Validation of our findings in larger sample sizes of different ethnicities would provide evidence on the role of variants of PI3K/AKT/mTOR pathway in developing BC.

Inhibition of PI3K/AKt/mTOR signaling pathway protects against d-galactosamine/lipopolysaccharide-induced acute liver failure by chaperone-mediated autophagy in rats

OBJECTIVE

This study aims to investigate the effects of PI3K/AKt/mTOR signaling pathway on the proliferation and apoptosis in acute liver failure (ALF) by chaperone mediated autophagy (CMA).

METHODS

The hepatocytes extracted from both normal rats and rats with ALF were assigned to control, acute injury, P13K agonist, and P13K inhibitor groups. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting were used as part of this investigation to detect the expression of PI3K/AKt/mTOR signaling pathway related-proteins (PI3K, AKt, mTOR), apoptosis related-proteins (Fas, Bax, Bcl-2), chaperone-mediated autophagy (CMA) marker proteins (LAMP-2A, HSC 70), p-PI3K, p-AKt, p-4E-BPI, and p-S6K. An MTT assay was used for analysis of cell proliferation after transfection. Flow cytometry is performed to detect the cell apoptosis.

RESULTS

In comparison to the normal group, the model group showed enhanced positive rate of PI3K, AKt, mTOR, increased expression levels of PI3K, AKt, mTOR, Fas, Bax, p-PI3K, p-AKt, p-4E-BPI and p-S6K, reduced expression levels of Bcl-2, LAMP-2A and HSC 70. The results in vitro experiment: compared with the acute injury group, the PI3K agonist group showed elevated expression levels of PI3K, AKt, mTOR, Fas, Bax, p-PI3K, p-AKt, p-4E-BPI and p-S6K, decreased expression levels of Bcl-2, LAMP-2A and HSC 70, inhibited cell proliferation, more arrested cells in G1 stage, and promoted cell apoptosis. Opposing this, the P13K inhibitor group exhibited an opposite trend.

CONCLUSION

In conclusion, inhibition of the PI3K/AKt/mTOR signaling pathway plays a protective role in ALF by promoting CMA expression, which could arrest cell proliferation and promote cell apoptosis.

Immunohistochemical Investigation of HER/AKT/mTOR Pathway and Cellular Adhesion Molecules in Urothelial Carcinomas

Background. Several investigators have suggested the possibility that the expression of both EGFR and HER2 could be utilized for molecularly targeted therapy in urinary bladder cancer. We tried to evaluate the expression of HER2 and EGFR and activation of the AKT/PTEN/mTOR pathway in urothelial carcinomas and if there is any association between them and cellular adhesion molecules (CAMs). Materials and Methods. Forty-one paraffin-embedded urothelial cancer tissue blocks were collected. Immunostains for HER2, EGFR, MIB1, phospho-AKT, PTEN, phospho-mTOR, e-cadherin, p-cadherin, and b-catenin were performed on tissue microarrays sections. The immunohistochemical results were correlated with clinicopathological parameters. Results. The overexpression of HER2 was found in 19.6% of the cases and it was associated with high grade tumors with a high mitotic index and phosphorylation of AKT and mTOR. Muscle-invasive tumors presented both cytoplasmic and nuclear losses of PTEN expression. There was no association between HER/AKT/mTOR pathway activation and CAM expression. Although cadherins were often coexpressed, only p-cadherin immunoreactivity was associated with tumor grade and high proliferative index. Conclusions. HER2 overexpression is found in a respective proportion of urothelial carcinomas. P-cadherin expression is associated with high grade UCs but it is not affected by HER2 overexpression or by activation of HER/AKT/mTOR pathway.

AMPKα Is Suppressed in Bladder Cancer through Macrophage-Mediated Mechanisms

Bladder cancer presents as either low- or high-grade disease, each with distinct mutational profiles; however, both display prominent mTORC1 activation. One major negative regulator of mTORC1 is AMPK, which is a critical metabolic regulator that suppresses cellular growth in response to metabolic stress by negatively regulating mTORC1. Alterations in the activation and protein levels of AMPK have been reported in breast, gastric, and hepatocellular carcinoma. To investigate whether AMPK suppression is responsible for mTOR activation in bladder cancer, the levels of AMPKα were quantified in a cohort of primary human bladder cancers and adjacent nontumor tissues. The levels of p-AMPKα, AMPKα1, AMPKα2, and total AMPKα were significantly suppressed in both low- and high-grade disease when compared with nontumor tissue. To elucidate the AMPKα suppression mechanism, we focused on inflammation, particularly tumor-infiltrating macrophages, due to their reported role in regulating AMPK expression. Treatment of HTB2 cancer cells with varying doses of differentiated U937 macrophage conditioned medium (CM) demonstrated a dose-dependent reduction of AMPKα protein. Additionally, macrophage CM treatment of HTB2 and HT1376 bladder cells for various times also reduced AMPKα protein but not mRNA levels. Direct TNFα treatment also suppressed AMPKα at the protein but not RNA level. Finally, staining of the human cohort for CD68, a macrophage marker, revealed that CD68+ cell counts correlated with reduced AMPKα levels. In summary, these data demonstrate the potential role for inflammation and inflammatory cytokines in regulating the levels of AMPKα and promoting mTORC1 activation in bladder cancer.

Mutation of genes of the PI3K/AKT pathway in breast cancer supports their potential importance as biomarker for breast cancer aggressiveness

Deregulation of phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway is closely associated with cancer development and cancer progression. PIK3CA, AKT1, and PTEN are the fundamental molecules of the PI3K/AKT pathway with increased mutation rates in cancer cases leading to aberrant regulation of the pathway. Even though molecular alterations of the PI3K/AKT pathway have been studied in breast cancer, correlations between specific molecular alterations and clinicopathological features remain contradictory. In this study, we examined mutations of the PI3K/AKT pathway in 75 breast carcinomas using high-resolution melting analysis and pyrosequencing, in parallel with analysis of relative expression of PIK3CA and AKT2 genes. Mutations of PIK3CA were found in our cohort in 21 cases (28 %), 10 (13 %) in exon 9 and 11(15 %) in exon 20. Mutation frequency of AKT1 and PTEN genes was 4 and 3 %, respectively. Overall, alterations in the PI3K/AKT signaling cascade were detected in 35 % of the cases. Furthermore, comparison of 50 breast carcinomas with adjacent normal tissues showed elevated PIK3CA messenger RNA (mRNA) levels in 18 % of tumor cases and elevated AKT2 mRNA levels in 14 %. Our findings, along with those of previous studies, underline the importance of the PI3K/AKT pathway components as potential biomarkers for breast carcinogenesis.

New and promising strategies in the management of bladder cancer

Bladder cancer is a complex and aggressive disease for which treatment strategies have had limited success. Improvements in detection, treatment, and outcomes in bladder cancer will require the integration of multiple new approaches, including genomic profiling, immunotherapeutics, and large randomized clinical trials. New and promising strategies are being tested in all disease states, including nonmuscle-invasive bladder cancer (NMIBC), muscle-invasive bladder cancer (MIBC), and metastatic urothelial carcinoma (UC). Efforts are underway to develop better noninvasive urine biomarkers for use in primary or secondary detection of NMIBC, exploiting our genomic knowledge of mutations in genes such as RAS, FGFR3, PIK3CA, and TP53 and methylation pathways alone or in combination. Recent data from a large, randomized phase III trial of adjuvant cisplatin-based chemotherapy add to our knowledge of the value of perioperative chemotherapy in patients with MIBC. Finally, bladder cancer is one of a growing list of tumor types that respond to immune checkpoint inhibition, opening the potential for new therapeutic strategies for treatment of this complex and aggressive disease.

BcCluster: A Bladder Cancer Database at the Molecular Level

BACKGROUND

Bladder Cancer (BC) has two clearly distinct phenotypes. Non-muscle invasive BC has good prognosis and is treated with tumor resection and intravesical therapy whereas muscle invasive BC has poor prognosis and requires usually systemic cisplatin based chemotherapy either prior to or after radical cystectomy. Neoadjuvant chemotherapy is not often used for patients undergoing cystectomy. High-throughput analytical omics techniques are now available that allow the identification of individual molecular signatures to characterize the invasive phenotype. However, a large amount of data produced by omics experiments is not easily accessible since it is often scattered over many publications or stored in supplementary files.

OBJECTIVE

To develop a novel open-source database, BcCluster (http://www.bccluster.org/), dedicated to the comprehensive molecular characterization of muscle invasive bladder carcinoma.

MATERIALS

A database was created containing all reported molecular features significant in invasive BC. The query interface was developed in Ruby programming language (version 1.9.3) using the web-framework Rails (version 4.1.5) (http://rubyonrails.org/).

RESULTS

BcCluster contains the data from 112 published references, providing 1,559 statistically significant features relative to BC invasion. The database also holds 435 protein-protein interaction data and 92 molecular pathways significant in BC invasion. The database can be used to retrieve binding partners and pathways for any protein of interest. We illustrate this possibility using survivin, a known BC biomarker.

CONCLUSIONS

BcCluster is an online database for retrieving molecular signatures relative to BC invasion. This application offers a comprehensive view of BC invasiveness at the molecular level and allows formulation of research hypotheses relevant to this phenotype.

Abnormal Protein Glycosylation and Activated PI3K/Akt/mTOR Pathway: Role in Bladder Cancer Prognosis and Targeted Therapeutics

Muscle invasive bladder cancer (MIBC, stage ≥T2) is generally associated with poor prognosis, constituting the second most common cause of death among genitourinary tumours. Due to high molecular heterogeneity significant variations in the natural history and disease outcome have been observed. This has also delayed the introduction of personalized therapeutics, making advanced stage bladder cancer almost an orphan disease in terms of treatment. Altered protein glycosylation translated by the expression of the sialyl-Tn antigen (STn) and its precursor Tn as well as the activation of the PI3K/Akt/mTOR pathway are cancer-associated events that may hold potential for patient stratification and guided therapy. Therefore, a retrospective design, 96 bladder tumours of different stages (Ta, T1-T4) was screened for STn and phosphorylated forms of Akt (pAkt), mTOR (pmTOR), S6 (pS6) and PTEN, related with the activation of the PI3K/Akt/mTOR pathway. In our series the expression of Tn was residual and was not linked to stage or outcome, while STn was statically higher in MIBC when compared to non-muscle invasive tumours (p = 0.001) and associated decreased cancer-specific survival (log rank p = 0.024). Conversely, PI3K/Akt/mTOR pathway intermediates showed an equal distribution between non-muscle invasive bladder cancer (NMIBC) and MIBC and did not associate with cancer-specif survival (CSS) in any of these groups. However, the overexpression of pAKT, pmTOR and/or pS6 allowed discriminating STn-positive advanced stage bladder tumours facing worst CSS (p = 0.027). Furthermore, multivariate Cox regression analysis revealed that overexpression of PI3K/Akt/mTOR pathway proteins in STn+ MIBC was independently associated with approximately 6-fold risk of death by cancer (p = 0.039). Mice bearing advanced stage chemically-induced bladder tumours mimicking the histological and molecular nature of human tumours were then administrated with mTOR-pathway inhibitor sirolimus (rapamycin). This decreased the number of invasive lesions and, concomitantly, the expression of STn and also pS6, the downstream effector of the PI3K/Akt/mTOR pathway. In conclusion, STn was found to be marker of poor prognosis in bladder cancer and, in combination with PI3K/Akt/mTOR pathway evaluation, holds potential to improve the stratification of stage disease. Animal experiments suggest that mTOR pathway inhibition could be a potential therapeutic approach for this specific subtype of MIBC.

Comprehensive Molecular Analysis of NSCLC; Clinicopathological Associations

Background

Selection of NSCLC patients for targeted therapy is currently based upon the presence of sensitizing mutations in EGFR and EML4/ALK translocations. The heterogeneity of molecular alterations in lung cancer has led to the ongoing discovery of potential biomarkers and targets in order to improve survival.

Aim

This study aimed to detect alterations in EGFR, KRAS, BRAF, PIK3CA, MET-gene copy number and ALK rearrangements in a large cohort of 956 NSCLC patients of Hellenic origin using highly sensitive techniques and correlations with clinicopathological characteristics.

Results

Mutations were detected in EGFR 10.6% (101 out of 956 samples), KRAS 26.5% (191 out of 720 samples), BRAF 2.5% (12 out of 471 samples), PIK3CA 3.8% (7 out of 184 samples), MET gene amplification was detected in 18% (31 out of 170) and ALK rearrangements in 3.7% (4 out of 107 samples). EGFR mutations were detected in exon 19 (61.4% of mutant cases), exon 21 p.Leu858Arg (19.8%), exon 20 (15.8%), exon 18 (2.9%) and were correlated with gender histology, smoking status and TTF1 staining. p.Thr790Met mutant cases (3.9%) displayed concurrent mutations in exons 19 or 21. Negative TTF-1 staining showed strong negative predictive value for the presence of EGFR mutations. KRAS mutations were associated with histology, the most common mutation being p.Gly12Cys (38%).

Discussion

In conclusion, only 89 patients were eligible for EGFR -TKIs and ALK inhibitors therapy, whereas 257 patients showed other alterations, highlighting the necessity for a detailed molecular profiling potentially leading to more efficient individualized therapies for NSCLC patients.

Molecular markers in bladder cancer: Novel research frontiers

Bladder cancer (BC) is a heterogeneous disease encompassing distinct biologic features that lead to extremely different clinical behaviors. In the last 20 years, great efforts have been made to predict disease outcome and response to treatment by developing risk assessment calculators based on multiple standard clinical-pathological factors, as well as by testing several molecular markers. Unfortunately, risk assessment calculators alone fail to accurately assess a single patient's prognosis and response to different treatment options. Several molecular markers easily assessable by routine immunohistochemical techniques hold promise for becoming widely available and cost-effective tools for a more reliable risk assessment, but none have yet entered routine clinical practice. Current research is therefore moving towards (i) identifying novel molecular markers; (ii) testing old and new markers in homogeneous patients' populations receiving homogeneous treatments; (iii) generating a multimarker panel that could be easily, and thus routinely, used in clinical practice; (iv) developing novel risk assessment tools, possibly combining standard clinical-pathological factors with molecular markers. This review analyses the emerging body of literature concerning novel biomarkers, ranging from genetic changes to altered expression of a huge variety of molecules, potentially involved in BC outcome and response to treatment. Findings suggest that some of these indicators, such as serum circulating tumor cells and tissue mitochondrial DNA, seem to be easily assessable and provide reliable information. Other markers, such as the phosphoinositide-3-kinase (PI3K)/AKT (serine-threonine kinase)/mTOR (mammalian target of rapamycin) pathway and epigenetic changes in DNA methylation seem to not only have prognostic/predictive value but also, most importantly, represent valuable therapeutic targets. Finally, there is increasing evidence that the development of novel risk assessment tools combining standard clinical-pathological factors with molecular markers represents a major quest in managing this poorly predictable disease.

Somatic Copy Number Abnormalities and Mutations in PI3K/AKT/mTOR Pathway Have Prognostic Significance for Overall Survival in Platinum Treated Locally Advanced or Metastatic Urothelial Tumors

BACKGROUND

An integrative analysis was conducted to identify genomic alterations at a pathway level that could predict overall survival (OS) in patients with advanced urothelial carcinoma (UC) treated with platinum-based chemotherapy.

PATIENTS AND METHODS

DNA and RNA were extracted from 103 formalin-fixed paraffin embedded (FFPE) invasive high-grade UC samples and were screened for mutations, copy number variation (CNV) and gene expression analysis. Clinical data were available from 85 cases. Mutations were analyzed by mass-spectrometry based on genotyping platform (Oncomap 3) and genomic imbalances were detected by comparative genomic hybridization (CGH) analysis. Regions with threshold of log2 ratio ≥0.4, or ≤0.6 were defined as either having copy number gain or loss and significantly recurrent CNV across the set of samples were determined using a GISTIC analysis. Expression analysis on selected relevant UC genes was conducted using Nanostring. To define the co-occurrence pattern of mutations and CNV, we grouped genomic events into 5 core signal transduction pathways: 1) TP53 pathway, 2) RTK/RAS/RAF pathway, 3) PI3K/AKT/mTOR pathway, 4) WNT/CTNNB1, 5) RB1 pathway. Cox regression was used to assess pathways abnormalities with survival outcomes.

RESULTS

35 samples (41%) harbored mutations on at least one gene: TP53 (16%), PIK3CA (9%), FGFR3 (2%), HRAS/KRAS (5%), and CTNNB1 (1%). 66% of patients had some sort of CNV. PIK3CA/AKT/mTOR pathway alteration (mutations+CNV) had the greatest impact on OS (p=0.055). At a gene level, overexpression of CTNNB1 (p=0.0008) and PIK3CA (p=0.02) were associated with shorter OS. Mutational status on PIK3CA was not associated with survival. Among other individually found genomic alterations, TP53 mutations (p=0.07), mTOR gain (p=0.07) and PTEN overexpression (p=0.08) have a marginally significant negative impact on OS.

CONCLUSIONS

Our study suggests that targeted therapies focusing on the PIK3CA/AKT/mTOR pathway genomic alterations can generate the greatest impact in the overall patient population of high-grade advanced UC.

Intravesical dual PI3K/mTOR complex 1/2 inhibitor NVP-BEZ235 therapy in an orthotopic bladder cancer model

NVP-BEZ235 is an inhibitor of both phosphatidylinositol 3-kinase (PI3K) and mammalian target of rapamycin complex 1/2 (mTORC1/2), and its antitumor activity is expected to be higher than that of mTORC1 inhibitors because it inhibits the upregulation of pAkt through mTORC2. We examined the efficacy of intravesical NVP-BEZ235 therapy in the treatment of bladder cancer using an orthotopic bladder cancer model. The cytotoxic effects of various concentrations of NVP-BEZ235 in MBT-2 cells were examined using a WST assay. The expression of pAkt, pS6 and p4EBP1 was evaluated in MBT-2 cells treated with NVP-BEZ235 using western blotting. Orthotopic models were established by implanting MBT-2 cells into the bladders of female C3H/He mice. We assigned C3H/He mice to 2 groups: a control group treated with vehicle control (n=15), and a group intravesically administered 40 µM (18.78 mg/l) of NVP-BEZ235 (n=15). NVP-BEZ235 inhibited the viability of MBT-2 cells in a dose-dependent manner. Furthermore, the expression of pAkt, pS6, and p4EBP1 was inhibited in NVP-BEZ235-treated MBT-2 cells. Bladder weights were significantly lower in the NVP-BEZ235-treated group than in the control group (P<0.05). An analysis of the tumor tissues revealed that the NVP-BEZ235 treatment strongly reduced pAkt, pS6 and p4EBP1 levels. An immunohistochemical analysis showed that NVP-BEZ235 significantly inhibited the expression of pS6. Intravesically administered NVP-BEZ235 exerted significant antitumor effects in the orthotopic bladder cancer model by inhibiting the PI3K/Akt/mTOR pathway. The intravesical instillation of a dual PI3K/mTORC1/2 inhibitor may represent a novel therapy for the treatment of bladder cancer.

Immunohistochemical and molecular analysis of PI3K/AKT/mTOR pathway in esophageal carcinoma

Among the numerous signaling pathways involved in tumorigenesis, PI3K-AKT-mTOR is a key one that regulates diverse cellular functions. However, its prognostic value in esophageal carcinoma remains unclear. In our study, we examined the immunohistochemical expression of phosphorylated (p-) AKT, mTOR, p70S6K and 4E-BP1 along with the mutational status of PIK3CA and AKT1 genes by High Resolution Melting Analysis and Pyrosequencing in 44 esophageal carcinomas. The results were correlated with the clinicopathological characteristics of the patients in an effort to define their possible prognostic significance. Total p-mTOR cytoplasmic expression, assessed in 10 random areas, was positively correlated with tumor stage (Kruskal-Wallis ANOVA, I/II vs III/IV, p = 0.0500). Μoreover, maximum p-mTOR cytoplasmic immunoexpression, estimated in hot spot areas, was positively associated with tumor grade (Mann-Whitney U test, I/II vs III, p = 0.0565). Interestingly, p-4E-BP1 immunoreactivity was negatively correlated with tumor histological grade (Mann-Whitney U test, I/II vs III, p = 0.0427). No mutation was observed in exons 9 and 20 of PIK3CA gene and in exon 4 of AKT1 gene. In conclusion, our findings depict the presence of activated PI3K/AKT/mTOR pathway in esophageal cancer bringing forward p-mTOR and p-4E-BP1 for their potential role in esophageal carcinogenesis. Additional studies are warranted to validate our findings.

Cellular senescence and aging: the role of B-MYB

Cellular senescence is a stable cell cycle arrest, caused by insults, such as: telomere erosion, oncogene activation, irradiation, DNA damage, oxidative stress, and viral infection. Extrinsic stimuli such as cell culture stress can also trigger this growth arrest. Senescence is thought to have evolved as an example of antagonistic pleiotropy, as it acts as a tumor suppressor mechanism during the reproductive age, but can promote organismal aging by disrupting tissue renewal, repair, and regeneration later in life. The mechanisms underlying the senescence growth arrest are broadly considered to involve p16(INK4A) -pRB and p53-p21(CIP1/WAF1/SDI1) tumor suppressor pathways; but it is not known what makes the senescence arrest stable and what the critical downstream targets are, as they are likely to be key to the establishment and maintenance of the senescent state. MYB-related protein B (B-MYB/MYBL2), a member of the myeloblastosis family of transcription factors, has recently emerged as a potential candidate for regulating entry into senescence. Here, we review the evidence which indicates that loss of B-MYB expression has an important role in causing senescence growth arrest. We discuss how B-MYB acts, as the gatekeeper, to coordinate transit through the cell cycle, in conjunction with the multivulval class B (MuvB) complex and FOXM1 transcription factors. We also evaluate the evidence connecting B-MYB to the mTOR nutrient signaling pathway and suggest that inhibition of this pathway leading to an extension of healthspan may involve activation of B-MYB.

In vivo disruption of an Rb-E2F-Ezh2 signaling loop causes bladder cancer

Bladder cancer is a highly prevalent human disease in which retinoblastoma (Rb) pathway inactivation and epigenetic alterations are common events. However, the connection between these two processes is still poorly understood. Here, we show that the in vivo inactivation of all Rb family genes in the mouse urothelium is sufficient to initiate bladder cancer development. The characterization of the mouse tumors revealed multiple molecular features of human bladder cancer, including the activation of E2F transcription factor and subsequent Ezh2 expression and the activation of several signaling pathways previously identified as highly relevant in urothelial tumors. These mice represent a genetically defined model for human high-grade superficial bladder cancer. Whole transcriptional characterizations of mouse and human bladder tumors revealed a significant overlap and confirmed the predominant role for Ezh2 in the downregulation of gene expression programs. Importantly, the increased tumor recurrence and progression in human patients with superficial bladder cancer is associated with increased E2F and Ezh2 expression and Ezh2-mediated gene expression repression. Collectively, our studies provide a genetically defined model for human high-grade superficial bladder cancer and demonstrate the existence of an Rb-E2F-Ezh2 axis in bladder whose disruption can promote tumor development.

Polycystin-1 and polycystin-2 are involved in the acquisition of aggressive phenotypes in colorectal cancer

The polycystins PC1 and PC2 are emerging as major players in mechanotransduction, a process that influences all steps of the invasion/metastasis cascade. We hypothesized that PC1 and PC2 facilitate cancer aggressiveness. Immunoblotting, RT-PCR, semi-quantitative and quantitative real-time PCR and FACS analyses were employed to investigate the effect of polycystin overexpression in colorectal cancer (CRC) cells. The impact of PC1 inhibition on cancer-cell proliferation was evaluated through an MTT assay. In vitro data were analyzed by Student's t-test. HT29 human xenografts were treated with anti-PC1 (extracellular domain) inhibitory antibody and analyzed via immunohistochemistry to determine the in vivo role of PC1 in CRC. Clinical significance was assessed by examining PC1 and PC2 protein expression in CRC patients (immunohistochemistry). In vivo and clinical data were analyzed by non-parametric tests, Kaplan-Meier curves, log-rank test and Cox model. All statistical tests were two-sided. PC1 overexpression promotes epithelial-to-mesenchymal transition (EMT) in HCT116 cells, while PC2 overexpression results in upregulation of the mTOR pathway in SW480 cells. PC1 inhibition causes reduced cell proliferation in CRC cells inducing tumor necrosis and suppressing EMT in HT29 tumor xenografts. In clinical study, PC1 and PC2 overexpression associates with adverse pathological parameters, including invasiveness and mucinous carcinomas. Moreover, PC1 overexpression appears as an independent prognostic factor of reduced recurrence-free survival (HR = 1.016, p = 0.03) and lowers overall survival probability, while aberrant PC2 expression predicts poor overall survival (p = 0.0468). These results support, for the first time, a direct link between mechanosensing polycystins (PC1 and PC2) and CRC progression.

Complex interactions between the components of the PI3K/AKT/mTOR pathway, and with components of MAPK, JAK/STAT and Notch-1 pathways, indicate their involvement in meningioma development

We investigated the significance of PI3K/AKT/mTOR pathway and its interactions with MAPK, JAK/STAT and Notch pathways in meningioma progression. Paraffin-embedded tissue from 108 meningioma patients was analysed for the presence of mutations in PIK3CA and AKT1. These were correlated with the expression status of components of the PI3K/AKT/mTOR pathway, including p85α and p110γ subunits of PI3K, phosphorylated (p)-AKT, p-mTOR, p-p70S6K and p-4E-BP1, as well as of p-ERK1/2, p-STAT3 and Notch-1, clinicopathological data and patient survival. A mutation in PIK3CA or AKT1 was found in around 9 % of the cases. Higher grade meningiomas displayed higher nuclear expression of p-p70S6K; higher nuclear and cytoplasmic expression of p-4E-BP1 and of Notch-1; lower cytoplasmic expression of p85αPI3K, p-p70S6K and p-ERK1/2; and lower PTEN Histo-scores (H-scores). PTEN H-score was inversely correlated with recurrence probability. In univariate survival analysis, nuclear expression of p-4E-BP1 and absence of p-ERK1/2 expression portended adverse prognosis, whereas in multivariate survival analysis, p-ERK1/2 expression emerged as an independent favourable prognostic factor. Treatment of the human meningioma cell line HBL-52 with the PI3K inhibitor LY294002 resulted in reduction of p-AKT, p-p70S6K and p-ERK1/2 protein levels. The complex interactions established between components of the PI3K/AKT/mTOR pathway, or with components of the MAPK, JAK/STAT and Notch-1 pathways, appear to be essential for facilitating and fuelling meningioma progression.

Phospho-mTOR in non-tumour and tumour bladder urothelium: Pattern of expression and impact on urothelial bladder cancer patients

Urothelial bladder carcinoma (UBC) is heterogeneous in its pathology and clinical behaviour. Evaluation of prognostic and predictive biomarkers is necessary, in order to produce personalised treatment options. The present study used immunohistochemistry to evaluate UBC sections containing tumour and non-tumour areas from 76 patients, for the detection of p-mTOR, CD31 and D2-40 (blood and lymphatic vessels identification, respectively). Of the non-tumour and tumour sections, 36 and 20% were scored positive for p-mTOR expression, respectively. Immunoexpression was observed in umbrella cells from non-tumour urothelium, in all cell layers from non-muscle-invasive (NMI) tumours (including expression in superficial cells), and in spots of cells from muscle-invasive (MI) tumours. Positive expression decreased from non-tumour to tumour urothelium, and from pT1/pTis to pT3/pT4 tumours; however, the few pT3/pT4 positive cases had worse survival rates, with 5-year disease-free survival being significantly lower. Angiogenesis occurrence was impaired in pT3/pT4 tumours that did not express p-mTOR. In conclusion, p-mTOR expression in non-tumour umbrella cells is likely a reflection of their metabolic plasticity, and extension to the inner layers of the urothelium in NMI tumours is consistent with an enhanced malignant potential. The expression in cell spots in a few MI tumours and absence of expression in the remaining tumours is intriguing and requires further research. Additional studies regarding the up- and downstream effectors of the mTOR pathway should be conducted.

Targeting the genetic alterations of the PI3K-AKT-mTOR pathway: its potential use in the treatment of bladder cancers

Urothelial carcinoma of the bladder is the most frequent tumor of the urinary tract and represents the fifth cause of death by cancer worldwide. The current first line chemotherapy is a combination of cisplatin and gemcitabine with median survival not exceeding 15months. Vinflunine is the only drug approved by EMEA as second-line treatment and few progresses have been made for the past 20years to increase the survival of metastatic patients, especially those who are not eligible for cisplatin-based regimen. The recent studies characterizing the genetic background of urothelial cancers of the bladder, revealed chromosomal alterations that are not seen at the same level in other types of cancers. This is especially the case for mutations of genes involved in the PI3K/AKT/mTOR signaling pathway that occupies a major place in the etiology of these tumors. Here, we describe the mutations leading to constitutive activation of the PI3K/AKT/mTOR pathway and discuss the potential use of the different classes of PI3K/AKT/mTOR inhibitors in the treatment of urothelial bladder cancers. Despite the recent pivotal study evidencing specific mutations of TSC1 in bladder cancer patients responding to everolimus and the encouraging results obtained with other derivatives than rapalogs, few clinical trials are ongoing in bladder cancers. Because of the genetic complexity of these tumors, the cross-talks of the PI3K/AKT/mTOR pathway with other pathways, and the small number of eligible patients, it will be of utmost importance to carefully choose the drugs or drug combinations to be further tested in the clinic.

Fibroblast growth factor receptor 3 activation plays a causative role in urothelial cancer pathogenesis in cooperation with Pten loss in mice

Although somatic mutations and overexpression of the tyrosine kinase fibroblast growth factor receptor 3 (FGFR3) are strongly associated with bladder cancer, evidence for their functional involvement in the pathogenesis remains elusive. Previously we showed that activation of Fgfr3 alone is not sufficient to initiate urothelial tumourigenesis in mice. Here we hypothesize that cooperating mutations are required for Fgfr3-dependent tumourigenesis in the urothelium and analyse a mouse model in which an inhibitor of Pi3k-Akt signalling, Pten, is deleted in concert with Fgfr3 activation (UroIICreFgfr3(+/) (K644E) Pten(flox) (/flox)). Two main phenotypical characteristics were observed in the urothelium: increased urothelial thickness and abnormal cellular histopathology, including vacuolization, condensed cellular appearance, enlargement of cells and nuclei, and loss of polarity. These changes were not observed when either mutation was present individually. Expression patterns of known urothelial proteins indicated the abnormal cellular differentiation. Furthermore, quantitative analysis showed that Fgfr3 and Pten mutations cooperatively caused cellular enlargement, while Pten contributed to increased cell proliferation. Finally, FGFR3 overexpression was analysed along the level of phosphorylated mTOR in 66 T1 urothelial tumours in tissue microarray, which supported the occurrence of functional association of these two signalling pathways in urothelial pathogenesis. Taken together, this study provides evidence supporting a functional role of FGFR3 in the process of pathogenesis in urothelial neoplasms. Given the wide availability of inhibitors specific to FGF signalling pathways, our model may open the avenue for FGFR3-targeted translation in urothelial disease.

The role of PTEN tumor suppressor pathway staining in carcinoma in situ of the bladder

OBJECTIVES

The PI3k/Akt pathway has been associated with the development and progression of bladder tumors, with most studies focused on papillary or muscle-invasive tumors. We sought to characterize the expression patterns of the PI3K/Akt pathway in a large cohort of high-risk preinvasive carcinoma in situ (CIS) tumors of the bladder. Our goal was to understand whether PI3K/Akt pathway alterations associated with CIS resemble early- or late-stage bladder cancers.

MATERIAL AND METHODS

We evaluated tissue specimens from 97 patients with CIS of the bladder, of which 14 had a concomitant papillary tumor. All patients were treated with intravesical bacillus Calmette-Guerin. All specimens were evaluated for PTEN, p-AKT, and p-S6 immunoreactivity. Markers were evaluated for percentage and intensity of staining and were scored using a 0 to 3+grading system.

RESULTS

PTEN staining was noted as least intense in 67% of tumor specimens and 22% of normal urothelium. P-Akt and p-S6 had intense staining in 77% and 90% of tumor specimens vs. 44% and 68% in normal tissue, respectively. Low-intensity staining for PTEN at 12 months correlated with higher recurrence risk (P = 0.026).

CONCLUSION

We describe a large cohort of CIS bladder tumors with decreased staining intensity of PTEN and increased staining intensity of p-AKT and p-S6, similar to high-grade and high-stage papillary tumors. Low-intensity staining of PTEN at 12 months was associated with an increased risk of recurrence.

P42 Ebp1 regulates the proteasomal degradation of the p85 regulatory subunit of PI3K by recruiting a chaperone-E3 ligase complex HSP70/CHIP

The short isoform of ErbB3-binding protein 1 (Ebp1), p42, is considered to be a potent tumor suppressor in a number of human cancers, although the mechanism by which it exerts this tumor-suppressive activity is unclear. Here, we report that p42 interacts with the cSH2 domain of the p85 subunit of phosphathidyl inositol 3-kinase (PI3K), leading to inhibition of its lipid kinase activity. Importantly, we found that p42 induces protein degradation of the p85 subunit and further identified HSP70/CHIP complex as a novel E3 ligase for p85 that is responsible for p85 ubiquitination and degradation. In this process, p42 couples p85 to the HSP70/CHIP-mediated ubiquitin–proteasomal system (UPS), thereby promoting a reduction of p85 levels both in vitro and in vivo. Thus, the tumor-suppressing effects of p42 in cancer cells are driven by negative regulation of the p85 subunit of PI3K.

PIK3CA gene alterations in bladder cancer are frequent and associate with reduced recurrence in non-muscle invasive tumors

Bladder cancer (BC) is the fifth most common cancer in the world, being the non-muscle invasive tumors (NMIBC) the most frequent. NMIBC shows a very high frequency of recurrence and, in certain cases, tumor progression. The phosphatidylinositol 3-kinase (PI3K) pathway, which controls cell growth, tumorigenesis, cell invasion and drug response, is frequently activated in numerous human cancers, including BC, in part through alterations of PIK3CA gene. However, the significance of PIK3CA gene alterations with respect to clinicopathological characteristics, and in particular tumor recurrence and progression, remains elusive. Here, we analyzed the presence of mutations in FGFR3 and PIK3CA genes and copy number alterations of PIK3CA gene in bladder tumor and their correspondent paired normal samples from 87 patients. We observed an extremely high frequency of PIK3CA gene alterations (mutations, copy gains, or both) in tumor samples, affecting primarily T1 and T2 tumors. A significant number of normal tissues also showed mutations and copy gains, being coincident with those found in the corresponding tumor sample. In low-grade tumors PIK3CA mutations associated with FGFR3 mutations. Alterations in PIK3CA gene resulted in increased Akt activity in tumors. Interestingly, the presence of PIK3CA gene alterations, and in particular gene mutations, is significantly associated with reduced recurrence of NMIBC patients. Importantly, the presence of FGFR3 mutations may influence the clinical outcome of patients bearing alterations in PIK3CA gene, and increased recurrence was associated to FGFR3 mutated, PIK3CA wt tumors. These findings may have high relevance in terms of using PI3K-targeted therapies for BC treatment.

PIK3CA, HRAS and PTEN in human papillomavirus positive oropharyngeal squamous cell carcinoma

Background

Recent genomic evidence suggests frequent phosphatidylinositide 3-kinase (PI3K) pathway activation in human papillomavirus (HPV) positive oropharyngeal squamous cell carcinoma. Mutations/amplification of the gene encoding p110α catalytic subunit of phosphoinositide 3-kinase (PIK3CA), loss of phosphatase and tensin homolog (PTEN) and HRAS mutations are known to activate PI3K pathway.

Methods and results

PIK3CA mutations were identified by Sanger sequencing in 23 of 75 (31%) HPV-positive oropharyngeal carcinomas, including exon 9 (p.E545K [n = 10] and p.E542K [n = 5]) or exon 20 (p.H1047Y, n = 2) mutations. Five rare and one novel (p.R537Q) PIK3CA mutations were identified. HRAS mutation (p.Q61L) was detected in 1 of 62 tested cases. PIK3CA amplification by fluorescence in situ hybridization (FISH) was identified in 4 cases (4/21, 20%), while PTEN loss was seen in 7 (7/21, 33%) cases (chromosome 10 monosomy [n = 4], homozygous deletion [n = 3]).

Conclusions

Overall, genetic alterations that likely lead to PI3K pathway activation were identified in 34 of 75 cases (45%) and did not correlate with disease specific survival. These findings offer a molecular rationale for therapeutic targeting of PI3K pathway in patients with HPV-positive oropharyngeal carcinoma.

Friend or foe: emerging role of nuclear factor kappa-light-chain-enhancer of activated B cells in cell senescence

The nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) proteins are a family of ubiquitously expressed transcription factors that regulate the response to cellular stress. They mediate innate and adaptive immunity through the initiation of an inflammatory response to pro-inflammatory signals. The role of persistent inflammation in aiding tumor development has led to the NF-κB family of transcription factors being strongly implicated in promoting cancer. However, recent studies have now revealed that NF-κB can also function as a tumor suppressor through the induction of cellular senescence. Cellular senescence is a stable cell cycle arrest that normal cells undergo in response to a variety of intrinsic and extrinsic stimuli including: progressive telomere shortening, changes in telomeric structure, or other forms of genotoxic stress. Senescence can compromise tissue repair and regeneration, contributing to tissue and organismal aging via the accumulation of senescent cells, depletion of stem/progenitor cells and secretion of an array of inflammatory cytokines, chemokines, and matrix metalloproteinases. Senescence can also lead to the removal of potentially cancerous cells, thereby acting as a potent tumor suppressor mechanism. Herein, we review the evidence indicating a role for NF-κB in tumor suppression via cellular senescence and suggest that depending upon the subunit expressed, the biological context, and the type and intensity of the signal, NF-κB can indeed promote senescence growth arrest.

A comprehensive immunohistochemical approach of AKT/mTOR pathway and p-STAT3 in mycosis fungoides

BACKGROUND

Although the expression pattern of phosphorylated (p)-mTOR pathway components has attracted scientific interest in several neoplasms, to our knowledge, there is no published information regarding its significance in mycosis fungoides (MF).

OBJECTIVE

We sought to perform a comprehensive simultaneous assessment of key members of AKT/mTOR pathway along with p-extracellular signal-regulated kinase (ERK), NOTCH1, and p-STAT3 in patients with MF.

METHODS

In all, 54 skin biopsy specimens (21 tumors, 30 plaques, and 3 folliculotropic MF) from 50 patients with MF were analyzed immunohistochemically for p-mTOR, its upstream p-AKT, its downstream effectors p-p70S6K and p-4E-BP1, and for p-ERK1/2, NOTCH1, and p-STAT3.

RESULTS

p-mTOR was coexpressed with p-p70S6K in 67.3% of lesions, but coexpression with other molecules was less common. p-p70S6K and marginally NOTCH1 displayed higher H-scores in tumors than in plaques. Significant correlations were recorded between p-ERK and p-4E-BP1, as well as between NOTCH1 and p-p70S6K or p-4E-BP1. NOTCH1, p-4E-BP1, and p-p70S6K expression were associated with advanced stage. In survival analysis simultaneous overexpression of p-AKT and p-p70S6K, along with p-4E-BP1 positivity, adversely affected cancer-specific, disease-free, and progression-free survival in advanced-stage cases.

LIMITATIONS

A limitation may be the small number of cases included in our investigation, precluding multivariate survival analysis.

CONCLUSIONS

Activation of AKT/mTOR pathway in MF appears to be correlated with NOTCH1, p-ERK, and p-STAT3 and is implicated in the acquisition of a more aggressive phenotype. The combination of p-AKT, p-p70S6K, and p-4E-BP1 emerges as a significant potential prognostic marker in patients with advanced stage.