Loss and reduced expression of PTEN correlate with advanced-stage gastric carcinoma

Evaluation of phosphatase and tensin homologue (PTEN) expression in gastric cancer and its relationship with histopathological findings

INTRODUCTION

Phosphatase and tensin homologue (PTEN) is an important tumour suppressor in multi-step tumorigenesis. To establish the role of PTEN in gastric cancer progression, we examined the PTEN expression degree in gastric cancer tissues. We also explained the connection between PTEN expression and histopathological findings.

MATERIALS AND METHODS

Our study was cross-sectional and made up of 50 patients with known gastric cancer. Immunohistochemical staining for PTEN was done on gastric cancer tissues. Tumour behaviour was estimated by histopathological assessments.

RESULTS

Twenty-seven (54%) of the 50 patients had PTEN staining. The evaluation of the connection between PTEN expression and demographic data and tumour behaviours revealed no meaningful relationship between PTEN expression and patients' age, gender, tumour site and size, tumour type, tumour grade and stage, neural, and lymphovascular invasion (P-value>0.05).

CONCLUSION

PTEN expression level is expected to be a significant molecular event in the progression of gastric cancer and may be a predictive marker for gastric cancer behaviours dependent on society.

Morphine-mediated release of astrocyte-derived extracellular vesicle miR-23a induces loss of pericyte coverage at the blood-brain barrier: Implications for neuroinflammation

Opioids such as morphine are the most potent and efficacious drugs currently available for pain management. Paradoxically, opioids have also been implicated in inducing neuroinflammation and associated neurocognitive decline. Pericytes, a critical component of the neurovascular unit (NVU), are centrally positioned between endothelial cells and astrocytes, maintaining function of the blood-brain barrier (BBB) nd regulating neuroinflammation by controlling monocyte influx under various pathological conditions. The role of pericytes in morphine-mediated neuroinflammation however, has received less attention, especially in the context of how pericytes crosstalk with other central nervous system (CNS) cells. The current study was undertaken to examine the effect of miRNAs released from morphine-stimulated human primary astrocyte-derived extracellular vesicles (morphine-ADEVs) in mediating pericyte loss at the blood-brain barrier, leading, in turn, to increased influx of peripheral monocytes. Our findings suggest that the heterogeneous nuclear ribonucleoprotein complex A2/B1 (hnRNP A2/B1) plays role in morphine-mediated upregulation and release of miR-23a in ADEVs, and through action of morphine via mu opioid receptor.We further demonstrated that miR-23a in morphine-ADEVs could be taken up by pericytes, resulting in downregulation of PTEN expression, ultimately leading to increased pericyte migration. Furthermore, both overexpression of PTEN and blocking the miR-23a target site at PTEN 3UTR (by transfecting miR-23a-PTEN target protector), attenuated morphine-ADEV-mediated pericyte migration. We also demonstrated that in the microvessels isolated from morphine-administered mice, there were fewer PDGFβR + pericytes co-localizing with CD31+ brain endothelial cells compared with those from saline mice. In line with these findings, we also observed increased loss of pericytes and a concomitantly increased influx of monocytes in the brains of morphine-administered pericyte-labeled NG2-DsRed mice compared with saline mice. In conclusion, our findings indicate morphine-ADEVs mediated loss of pericyte coverage at the brain endothelium, thereby increasing the influx of peripheral monocytes in the central nervous system, leading to neuroinflammation.

Synergistic effects of Rapamycin and Fluorouracil to treat a gastric tumor in a PTEN conditional deletion mouse model

The tumor suppressor gene phosphatase and tensin homolog (PTEN) in PI3K/Akt/mTOR pathway is essential in inhibiting tumor growth and metastasis. However, whether the mutation of PTEN gene could induce tumorigenesis and impact the treatment of gastric cancer is still unclear. The purpose of the study was to investigate the combined treatment of gastric tumorigenesis using Rapamycin and Fluorouracil (5-Fu) through interfering with the Akt/mTOR pathway in a mouse model with PTEN conditional deletion. Three groups of mice were exposed for 5 days to Rapamycin and 5-Fu separately and together. The gene expression of the Akt/mTOR pathway, the protein expression of caspase-3 and p-Akt, p-S6K and p-4EBP1, and the pathological changes in stomachs were analyzed. Our study demonstrates that the conditional PTEN deletion in the cells of glandular stomach induces hyperplastic gastric tumors in mice. The combined Rapamycin administration with 5-Fu resulted in better outcomes than their separate administration for the treatment of gastric cancer by inhibiting the mTOR signal pathway. Our study indicates that Rapamycin has a synergistic interaction with chemotherapeutic 5-Fu, and demonstrates a potential therapeutic combination treatment on glandular stomach tumor with PTEN functional absence or aberrantly activated Akt/mTOR pathway. It provides important insights into the inhibition of the Akt/mTOR pathway in gastric cancer clinical therapy.

Current advances in prognostic and diagnostic biomarkers for solid cancers: Detection techniques and future challenges

Solid cancers are one of the leading causes of cancer related deaths, characterized by rapid growth of tumour, and local and distant metastases. Current advances on multimodality care have substantially improved local control and metastasis-free survival of patients by resection of primary tumour. The major concern in disease prognosis is the timely detection of resectable or metastatic tumour, thus reinforcing the need for identification of biomarkers for premalignant lesions of solid cancer. This ultimately improves the outcome for the patients. Therefore, the purpose of this review is to update the recent advancements on prognostic and diagnostic biomarkers to enhance early detection of common solid cancers including, breast, lung, colorectal, prostate and stomach cancer. We also provide an insight into Food and Drug Administration (FDA)-approved solid cancers biomarkers; various conventional techniques used for detection of prognostic and diagnostic biomarkers and discuss approaches to turn challenges in this field into opportunities.

Biological implications of PTEN upregulation and altered sodium/iodide symporter intracellular distribution in resveratrol-suppressed anaplastic thyroid cancer cells

Objective: Anaplastic thyroid cancer/ATC is a highly aggressive malignancy with extremely poor prognosis. Resveratrol/Res promotes re-differentiation of cancer cells and exerts inhibitory effects on ATC cells. Sodium/iodide symporter/NIS and phosphate and tension homology deleted on chromsome ten/PTEN levels are positively correlated with the grade of thyroid cancer differentiation, while the impact of Res on them remain unknown.

Materials and Methods: The patterns of NIS and PTEN expression and intracellular distribution in THJ-16T and THJ-21T ATC and Nthy-ori 3-1 normal thyroid cells and their relevance with Res-caused ATC suppression were investigated via multiple experimental methods. E-cadherin was cited as a re-differentiation biomarker of ATC cells.

Results: MTT and EdU cell proliferation assays showed distinct growth suppression in ATC cells after Res treatment. TUNEL staining revealed extensive apoptosis of Res-treated THJ-16T and THJ-21T rather than Nthy-ori 3-1 cells. Western blotting, immunocytochemical/ICC and double-labeled immunofluorescent/IF staining showed increased PTEN levels accompanied with distinct NIS and PTEN nuclear co-translocation in Res-treated THJ-16T and THJ-21T cells. E-cadherin but not NIS appeared on the outer membrane.

Conclusion: PTEN upregulation and the concurrent NIS and PTEN nuclear translocation in Res-suppressed ATC cells may indicate the better therapeutic outcome and would be a group of beneficial prognostic factors of ATCs.

Expression and clinical correlation of Survivin and PTEN in gastric cancer patients

Reports on the correlation between the expression of Survivin/phosphatase and tensin homolog (PTEN) proteins and clinical factors in gastric cancer (GC) are varied, and the sample sizes were also not sufficient. The present study aimed to detect the expression of Survivin and PTEN proteins in GC patients on the basis of a greater number of specimens and to analyze the correlation with clinical features and survival. The results revealed that the Survivin expression rates in GC, normal tissues and metastatic lymph nodes were 72% (232/322), 5% (6/120) and 80% (36/45), respectively, while the PTEN expression rates were 34% (109/322), 92.5% (111/120) and 24.4% (11/45), respectively, and the differences between cancer and normal tissue or metastatic lymph nodes were significant for both proteins (P<0.05). The expression of Survivin was significantly associated with gross type, depth of invasion, distant metastasis, tumor, necrosis and metastasis (TNM) stage and vascular invasion, while PTEN expression was predominantly associated with age, tumor size, invasion depth, TNM stage and lymphatic invasion in GC patients (P<0.05). The expression of both was associated with postoperative metastasis and metastatic site (P=0.007 and P=0.011 for Survivin, and P=0.002 and P=0.005 for PTEN). There was a negative association between the expression levels of Survivin and PTEN (P=0.001, r=−0.524). The expression levels of both were also associated with prognosis. The expression of Survivin and PTEN protein exhibit opposing trends in GC, which may indicate adverse biological effects in the occurrence of GC. The Survivin and PTEN expression levels are likely to be an important molecular event in gastric tumorigenesis and may be considered as molecular markers of GC progression and reliable prognostic indicators of GC.

Targeting the histone demethylase PHF8-mediated PKCα-Src-PTEN axis in HER2-negative gastric cancer

Targeted treatments for advanced gastric cancer (GC) are needed, particularly for HER2-negative GC, which represents the majority of cases (80 to 88%). In this study, in silico analyses of the lysine histone demethylases (KDMs) involved in diverse biological processes and diseases revealed that PHD finger protein 8 (PHF8, KDM7B) was significantly associated with poor clinical outcome in HER2-negative GC. The depletion of PHF8 significantly reduced cancer progression in GC cells and in mouse xenografts. PHF8 regulated genes involved in cell migration/motility based on a microarray analysis. Of note, PHF8 interacted with c-Jun on the promoter of PRKCA which encodes PKCα. The depletion of PHF8 or PKCα greatly up-regulated PTEN expression, which could be rescued by ectopic expression of a PKCα expression vector or an active Src. These suggest that PTEN destabilization occurs mainly via the PKCα-Src axis. GC cells treated with midostaurin or bosutinib significantly suppressed migration in vitro and in zebrafish models. Immunohistochemical analyses of PHF8, PKCα, and PTEN showed a positive correlation between PHF8 and PKCα but negative correlations between PHF8 and PTEN and between PKCα and PTEN. Moreover, high PHF8-PKCα expression was significantly correlated with worse prognosis. Together, our results suggest that the PKCα-Src-PTEN pathway regulated by PHF8/c-Jun is a potential prognostic/therapeutic target in HER2-negative advanced GC.

Low expression of adenomatous polyposis coli 2 correlates with aggressive features and poor prognosis in colorectal cancer

Currently, there are no relevant findings on the diagnostic and prognostic roles of adenomatous polyposis coli 2 (APC2) in colorectal cancer (CRC). This study investigated the clinical value of APC2 dysregulation in the prognosis of CRC. Immunohistochemical scores obtained from tissue microarrays were used to quantify the expression of APC2 protein in 201 CRC tissues and 139 adjacent normal tissues. A chi-squared test was performed to analyze the association between APC2 expression and various clinical characteristics. Differences in 5-year survival between groups were analyzed. A receiver operating characteristic (ROC) curve was generated to investigate the potential association between APC2 and CRC diagnosis. Compared with adjacent normal tissues, APC2 was downregulated in CRC tissues (P = 0.0004). Survival analyses revealed that CRC patients with high APC2 expression (96.74%) obtained better 5-year survival rates than those with low APC2 expression (88.07%). CRC patients with low APC2 expression exhibited obvious lymphovascular invasion (P = 0.010), lymph node metastasis (P = 0.007), and high tumor node metastasis (TNM) stage (P = 0.007). Furthermore, ROC curves confirmed that APC2 was associated with lymphovascular invasion (P = 0.004), lymph node metastasis (P = 0.002), and TNM staging (P = 0.002). In summary, low APC2 expression in CRC tissues was associated with poor prognosis and may be a useful biomarker for the prognosis and clinical classification of CRC.

PTEN, a Barrier for Proliferation and Metastasis of Gastric Cancer Cells: From Molecular Pathways to Targeting and Regulation

Cancer is one of the life-threatening disorders that, in spite of excellent advances in medicine and technology, there is no effective cure for. Surgery, chemotherapy, and radiotherapy are extensively applied in cancer therapy, but their efficacy in eradication of cancer cells, suppressing metastasis, and improving overall survival of patients is low. This is due to uncontrolled proliferation of cancer cells and their high migratory ability. Finding molecular pathways involved in malignant behavior of cancer cells can pave the road to effective cancer therapy. In the present review, we focus on phosphatase and tensin homolog (PTEN) signaling as a tumor-suppressor molecular pathway in gastric cancer (GC). PTEN inhibits the PI3K/Akt pathway from interfering with the migration and growth of GC cells. Its activation leads to better survival of patients with GC. Different upstream mediators of PTEN in GC have been identified that can regulate PTEN in suppressing growth and invasion of GC cells, such as microRNAs, long non-coding RNAs, and circular RNAs. It seems that antitumor agents enhance the expression of PTEN in overcoming GC. This review focuses on aforementioned topics to provide a new insight into involvement of PTEN and its downstream and upstream mediators in GC. This will direct further studies for evaluation of novel signaling networks and their targeting for suppressing GC progression.

Novel Therapeutic Approaches of Ion Channels and Transporters in Cancer

The expression and function of many ion channels and transporters in cancer cells display major differences in comparison to those from healthy cells. These differences provide the cancer cells with advantages for tumor development. Accordingly, targeting ion channels and transporters have beneficial anticancer effects including inhibition of cancer cell proliferation, migration, invasion, metastasis, tumor vascularization, and chemotherapy resistance, as well as promoting apoptosis. Some of the molecular mechanisms associating ion channels and transporters with cancer include the participation of oxidative stress, immune response, metabolic pathways, drug synergism, as well as noncanonical functions of ion channels. This diversity of mechanisms offers an exciting possibility to suggest novel and more effective therapeutic approaches to fight cancer. Here, we review and discuss most of the current knowledge suggesting novel therapeutic approaches for cancer therapy targeting ion channels and transporters. The role and regulation of ion channels and transporters in cancer provide a plethora of exceptional opportunities in drug design, as well as novel and promising therapeutic approaches that may be used for the benefit of cancer patients.

PTEN Protein Loss and Loss-of-Function Mutations in Gastric Cancers: The Relationship with Microsatellite Instability, EBV, HER2, and PD-L1 Expression

Inactivation of phosphatase and tensin homolog (PTEN) is caused by multiple mechanisms, and loss of PTEN activity is related to the progression of various cancers. In gastric cancer (GC), the relationship between the loss of PTEN protein expression and various genetic alterations remains unclear. The effects of microsatellite instability (MSI), Epstein–Barr virus (EBV), HER2 overexpression, and PD-L1 expression on PTEN mutation have not been fully explored. We performed comprehensive cancer panel tests with a cohort of 322 tumor samples from patients with advanced GC. Immunohistochemistry for PTEN protein was performed in all cases, and the loss of protein expression was defined as a complete absence of nuclear staining. In total, 34 cases (10.6%) had pathogenic PTEN mutations, of which 19 (55.9%) showed PTEN protein loss. The most common PTEN variants associated with protein loss were p.R130 (n = 4) followed by p.R335, p.L265fs, and deletions (n = 2). All the ten nonsense mutations identified in the samples resulted in PTEN inactivation. In the remaining 288 GC cases with wild-type PTEN, protein loss was found in 35 cases (12.2%). Thus, PTEN mutations were significantly associated with PTEN protein loss (p = 5.232 × 10⁻¹⁰), high MSI (p = 3.936 × 10⁻⁸), and EBV-positivity (p = 0.0071). In conclusion, our results demonstrate that loss-of-function mutations in PTEN are a frequent genetic mechanism of PTEN inactivation in GC.

Multifaceted Regulation of PTEN Subcellular Distributions and Biological Functions

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a tumor suppressor gene frequently found to be inactivated in over 30% of human cancers. PTEN encodes a 54-kDa lipid phosphatase that serves as a gatekeeper of the phosphoinositide 3-kinase pathway involved in the promotion of multiple pro-tumorigenic phenotypes. Although the PTEN protein plays a pivotal role in carcinogenesis, cumulative evidence has implicated it as a key signaling molecule in several other diseases as well, such as diabetes, Alzheimer's disease, and autism spectrum disorders. This finding suggests that diverse cell types, especially differentiated cells, express PTEN. At the cellular level, PTEN is widely distributed in all subcellular compartments and organelles. Surprisingly, the cytoplasmic compartment, not the plasma membrane, is the predominant subcellular location of PTEN. More recently, the finding of a secreted 'long' isoform of PTEN and the presence of PTEN in the cell nucleus further revealed unexpected biological functions of this multifaceted molecule. At the regulatory level, PTEN activity, stability, and subcellular distribution are modulated by a fascinating array of post-translational modification events, including phosphorylation, ubiquitination, and sumoylation. Dysregulation of these regulatory mechanisms has been observed in various human diseases. In this review, we provide an up-to-date overview of the knowledge gained in the last decade on how different functional domains of PTEN regulate its biological functions, with special emphasis on its subcellular distribution. This review also highlights the findings of published studies that have reported how mutational alterations in specific PTEN domains can lead to pathogenesis in humans.

Prognostic importance of PTEN, EGFR, HER-2, and IGF-1R in gastric cancer patients treated with postoperative chemoradiation

Background/aim

This study aimed to describe the prognostic importance of epidermal growth factor (EGFR), phosphatase and tensin homolog (PTEN), human EGF receptor-2 (HER-2), and insulin-like growth factor 1 receptor (IGF-1R) in gastric cancer patients treated with postoperative chemoradiation therapy.

Materials and methods

Sixty-nine patients treated with adjuvant chemoradiation therapy were retrospectively evaluated. Tumor samples were stained immunohistochemically.

Results

All patients were treated with 3D conformal radiation therapy with concomitant and adjuvant chemotherapy. Perineural invasion (PNI) (P = 0.042), prechemoradiation therapy albumin levels below 3.5 mg/dL (P = 0.011), and EGFR positivity (P = 0.008) had negative effects on overall survival (OS). The median OS was 26 months for patients with PNI (+), 34.9 months for those with PNI (–), 19.5 months for those with albumin levels below 3.5 mg/dL, and 33.2 months for those with albumin levels above 3.5 mg/dL. IGF-1R (+) (P = 0.035) and history of cigarette smoking (P = 0.033) were observed to have a statistically significantly negative effect on disease-free survival (DFS). The median DFS was 29.2 months for IGF-1R (+) patients, 37.9 months for those with IGF-1R (-), and 26.3 and 40.59 months for smokers and nonsmokers, respectively.

Conclusion

IGF-1R and EGFR may be used for patient selection in future prospective studies that evaluate the prognostic importance of these receptors.

TRPM2 ion channel promotes gastric cancer migration, invasion and tumor growth through the AKT signaling pathway

Transient Receptor Potential Melastatin-2 (TRPM2) ion channel is emerging as a great therapeutic target in many types of cancer, including gastric cancer - a major health threat of cancer related-death worldwide. Our previous study demonstrated the critical role of TRPM2 in gastric cancer cells bioenergetics and survival; however, its role in gastric cancer metastasis, the major cause of patient death, remains unknown. Here, using molecular and functional assays, we demonstrate that TRPM2 downregulation significantly inhibits the migration and invasion abilities of gastric cancer cells, with a significant reversion in the expression level of metastatic markers. These effects were concomitant with decreased Akt and increased PTEN activities. Finally, TRPM2 silencing resulted in deregulation of metastatic markers and abolished the tumor growth ability of AGS gastric cancer cells in NOD/SCID mice. Taken together, our results provide compelling evidence on the important function of TRPM2 in the modulation of gastric cancer cell invasion likely through controlling the PTEN/Akt pathway.

Significance of EGFR and PTEN Expression and PLR and NLR for Predicting the Prognosis of Epithelioid Malignant Peritoneal Mesothelioma

Objective

The aim of our study was to investigate the expression of EGFR and PTEN in tissues and measure the serum platelet-to-lymphocyte ratio (PLR) and neutrophil-to-lymphocyte ratio (NLR) to evaluate the prognostic factors of patients with epithelioid malignant peritoneal mesothelioma (MPeM).

Methods

33 patients of pathologically diagnosed epithelioid MPeM tissues were analyzed using immunohistochemistry to detect EGFR and PTEN; the PLR and NLR were determined by using a routine blood test. We analyzed the relationships of these markers to age, sex, asbestos exposure, elevated platelet count, ascites, and clinical stage.

Results

EGFR and PTEN expressions were positive in 22 (66.67%) and 7 (21.21%) epithelioid MPeM patients, respectively. However, these two markers as well as PLR and NLR were not significantly associated with age, sex, asbestos exposure, elevated platelet counts, ascites, and clinical stage (P > 0.05). The correlation between EGFR and PTEN was negative (r = −0.577, P < 0.001), but the correlation between NLR and PLR was positive (r = 0.456, P = 0.008). The median survival of all patients was 6 months. In univariate analysis, PTEN (P < 0.001), PLR (P = 0.014), and NLR (P = 0.015) affected the overall survival. Multivariate analysis revealed that PTEN and PLR were validated as predictive for overall survival of epithelioid MPeM (HR = 0.070, P = 0.001, and HR = 3.379, P = 0.007, respectively).

Conclusion

On the basis of these results, it is suggested that PTEN and PLR are risk factors for the prognosis of epithelioid MPeM, which may be targets for selective therapies and improve the outcomes of patients with epithelioid MPeM.

The contrary functions of lncRNA HOTAIR/miR-17-5p/PTEN axis and Shenqifuzheng injection on chemosensitivity of gastric cancer cells

This study was implemented to figure out whether lncRNA HOTAIR/miR‐17‐5p/PTEN axis played a role that was opposite to Shenqifuzheng (SQFZ) injection in regulating the chemosensitivity of gastric cancer cells. The gastric cancer tissues were gathered and four gastric cancer cell lines were prepared, including BGC‐823, MGC‐803, SGC‐7901, and MKN28. Moreover, cisplatin, adriamycin, mitomycin, and 5‐fluoroura were managed as the chemo‐therapeutics, and SQFZ was prepared as a Chinese medicine. Striking distinctions of HOTAIR, miR‐17‐5p, and PTEN expressions were observed between gastric cancer tissues and para‐carcinoma normal tissues (P < 0.05). MKN28 was associated with the highest resistance to cisplatin, adriamycin, mitomycin, and 5‐fluoroura among all the cell types, and SQFZ significantly improved the MKN28 cells’ sensitivity to the drugs (P < 0.05). The over‐expressed HOTAIR and miR‐17‐5p, as well as under‐expressed PTEN tended to significantly facilitate the viability, EMT process and proliferation of MKN28 cells that were subject to treatment of chemo‐therapies (P < 0.05). SQFZ could amplify the effects of si‐HOTAIR, miR‐17‐5p inhibitor, and pcDNA‐PTEN on boosting the chemosensitivity of gastric cancer cells (P < 0.05). In addition, HOTAIR was also found to directly target miR‐17‐5p, and PTEN appeared to be subject to the modification of HOTAIR and miR‐17‐5p in its acting on the viability, proliferation, EMT process, and apoptosis of gastric cancer cells. The HOTAIR/miR‐17‐5p/PTEN axis could be regarded as the potential treatment targets for gastric cancer, and adjuvant therapy of SQFZ injection could assist in further improving the treatment efficacy of chemo‐therapies for gastric cancer.

Functional long non-coding RNAs associated with gastric cancer susceptibility and evaluation of the epidemiological efficacy in a central Chinese population

AIM

To screen and validate the gastric cancer-associated long non-coding RNAs (lncRNAs) and their functional single nucleotide polymorphisms (SNPs).

METHODS

Based on case-control design, we select the differentially expressed lncRNAs by bioinformation tools and validate SNPs in lncRNAs genes in population. Attributable risk percentage (ARP) and population attributable risk percentage (PARP) were used to assess the effect of epidemiology.

RESULTS

Four lncRNAs with SNPs (lnc-EVX1-3:3 (rs1859168), lnc-MACC1-1:7 (rs3815254), lnc-AMFR-1:1 (rs4784659) and lnc-ZNF33B-2:1 (rs579501)) were selected to be validated in population. The unconditional multiple logistic regression based on the dominant (odds ratio, OR=0.64, 95%confidence interval, 95%CI: 0.47-0.86) and recessive genetic model (OR=1.77, 95%CI: 1.34-2.35) showed rs1859168 was significantly associated with lower risk of gastric cancer. The dominant (OR=0.42, 95%CI:0.31-0.57) and additive (OR=0.52, 95%CI:0.40-0.67) genetic model revealed that rs4784659 decreased the risk of gastric cancer. Similarly, the dominant (OR=0.72, 95%CI: 0.52-0.98) and additive (OR=0.73, 95%CI: 0.56-0.97) genetic model showed the individuals with rs579501 had reduced risk of gastric cancer. Whereas no statistical association between rs3815254 and gastric cancer. ARP and PARP for gastric cancer associated with rs1859168 in dominant model (56.25%, 33.05%), and in recessive model (43.50% and 29.37%). For rs4784659, ARP and PARP were 138.09% and 10.39% in dominant model, 92.31% and 8.76% in additive model. For rs579501, ARP and PARP were 38.89% and 4.03% in dominant model, 36.99% and 3.88% in additive model.

CONCLUSION

Our findings showed rs4784659, rs579501 and rs1859168 reduced the susceptibility of gastric cancer. From epidemiological perspective, the lncRNAs with SNPs attenuate the development of gastric cancer.

Association of PTEN expression with biochemical recurrence in prostate cancer: results based on previous reports

Purpose

Among men, prostate cancer (PCa) is one of the most commonly diagnosed cancers and the leading cause of cancer death worldwide. Phosphatase and tension homolog (PTEN) acts as a negative regulator of the phosphatidylinositol 3-kinase (PIK3)/Akt pathway and suppresses tumor progression. Meanwhile, PTEN is frequently deleted in PCa. Identifying the specific molecular markers of biochemical recurrence (BCR) in PCa patients is critical in clinical practice. Our systematic review summarizes the evidence about the PTEN expression and BCR rate in PCa patients.

Methods

To clarify the impact of PTEN expression on the PCa BCR rate, a systematic review and meta-analysis was performed by searching the PubMed, Embase, and Web of Science databases, to identify the relevant literature. The analysis of pooled data was performed with Stata 12. The combined odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were evaluated by the fixed-effects or random-effects models. The combined sensitivity and publication bias were also estimated.

Results

In total, nine articles containing ten independent cohort studies, including 2,154 cases with positive expression of PTEN and 1,006 PTEN deletion cases, were deemed eligible for the meta-analysis. Overall, the positive expression of PTEN was associated with a significantly lower BCR rate (OR =0.521, 95% CI: 0.431–0.630). Subgroup analysis stratified by race revealed that in multiple races (OR =0.215, 95% CI: 0.072–0.648) and Caucasian (OR =0.469, 95% CI: 0.373–0.591) races, positive expression of PTEN showed a significant association with lower BCR rate. Subgroup analysis also showed the significant result in different sample sizes.

Conclusion

PTEN deletion has a relationship with a higher BCR rate in PCa compared with positive expression of PTEN.

Immunohistochemical analysis of PTEN, HER2/neu, and ki67 expression in patients with gastric cancer and their association with survival

BACKGROUND

Considering the poor prognosis of patients with gastric cancer, molecular diagnostic and prognostic markers for this cancer should be established. The aims of our study were to assess the correlations between PTEN, HER2/neu, and Ki67 expressions and clinicopathological factors of gastric cancer patients in upper Egypt, as well as their influence on OS and DFS.

PATIENTS AND METHODS

In this descriptive-analytic study, 42 patients with gastric carcinoma treated by postioerative chemoradiation between 2004 and 2014. Pathological review was done. Immunohistochemical staining and evaluation were performed.

RESULTS

All the studied markers were significantly correlated with increased TNM stage. Her2/neu overexpression and positive Ki67 expression were significantly associated with histological grade. High percentage of positive Her2/neu and Ki67expression was found in gastric carcinoma tissue samples which lack PTEN expression. The one-year OS rate for the entire group (n=42) was 77.4%, whereas the DFS rate was 45%. Pathological T stage PTEN status significantly affected both OS (p=0.029 and 0.027 respectively) and DFS (p=0.006 and 0.012 respectively) rates. Multivariate Cox analyses showed that only pathological T stage was an independent prognostic factor affecting OS (P=0. 007, HR: 2.02; 95% CI: 1.2-3.38)and DFS(P<0.0001, HR: 2.69; 95% CI: 1.54-4.69).

CONCLUSION

All the studied molecular markers, was significantly correlated with pathological T stage that significantly affected both OS and DFS rates. These findings indicate that these markers have an important role in gastric cancer growth and dissemination so these markers can be used as a prognostic biomarker. In addition, therapies targeting Her2 and PTEN may help develop novel therapeutics for gastric cancer.

Loss of Expression of PTEN is Associated with Worse Prognosis in Patients with Cancer

BACKGROUND

The tumor suppressor phosphatase and tensin homolog (PTEN) is an important negative regulator of cell-survival signaling. However, available results for the prognostic value of PTEN expression in patients with cancer remain controversial. Therefore, a meta-analysis of published studies investigating this issue was performed.

MATERIALS AND METHODS

A literature search via PubMed and EMBASE databases was conducted. Statistical analysis was performed by using the STATA 12.0 (STATA Corp., College, TX). Data from eligible studies were extracted and included into the meta-analysis using a random effects model.

RESULTS

A total of 3,810 patients from 27 studies were included in the meta-analysis, 22 investigating the relationship between PTEN expression and overall survival (OS) using univariate analysis, and nine with multivariate analysis. The pooled hazard ratio (HR) for OS was 1.64 (95% confidence interval (CI): 1.32-2.05) by univariate analysis and 1.56 (95% CI: 1.20-2.03) by multivariate analysis. In addition, eight papers including two disease-free-survival analyses (DFSs), four relapse-free-survival analyses (RFSs), three progression-free-survival analyses (PFSs) and one metastasis-free-survival analysis (MFS) reported the effect of PTEN on survival. The results showed that loss of PTEN expression was significant correlated with poor prognosis, with a combined HR of 1.74 (95% CI: 1.24-2.44). Furthermore, in the stratified analysis by the year of publication, ethnicity, cancer type, method, cut- off value, median follow-up time and neoadjuvant therapy in which the study was conducted, we found that the ethnicity, cancer type, method, median follow-up time and neoadjuvant therapy are associated with prognosis.

CONCLUSIONS

Our study shows that negative or loss of expression of PTEN is associated with worse prognosis in patients with cancer. However, adequately designed prospective studies need to be performed for confirmation.

Melittin restores PTEN expression by down-regulating HDAC2 in human hepatocelluar carcinoma HepG2 cells

Melittin is a water-soluble toxic peptide derived from the venom of the bee. Although many studies show the anti-tumor activity of melittin in human cancer including glioma cells, the underlying mechanisms remain elusive. Here the effect of melittin on human hepatocelluar carcinoma HepG2 cell proliferation in vitro and further mechanisms was investigated. We found melittin could inhibit cell proliferation in vitro using Flow cytometry and MTT method. Besides, we discovered that melittin significantly downregulated the expressions of CyclinD1 and CDK4. Results of western Blot and Real-time PCR analysis indicated that melittin was capable to upregulate the expression of PTEN and attenuate histone deacetylase 2 (HDAC2) expression. Further studies demonstrated that knockdown of HDAC2 completely mimicked the effects of melittin on PTEN gene expression. Conversely, it was that the potential utility of melittin on PTEN expression was reversed in cells treated with a recombinant pEGFP-C2-HDAC2 plasmid. In addition, treatment with melittin caused a downregulation of Akt phosphorylation, while overexpression of HDAC2 promoted Akt phosphorylation. These findings suggested that the inhibitory of cell growth by melittin might be led by HDAC2-mediated PTEN upregulation, Akt inactivation, and inhibition of the PI3K/Akt signaling pathways.

Altered Expression of PTEN and Its Major Regulator MicroRNA-21 in Pulmonary Neuroendocrine Tumors

Background

Phosphatase and tensin homolog on chromosome ten (PTEN) is one of the most frequently inactivated tumor suppressors in various tumor types. MicroRNA-21 (miR-21) may affect tumor progression by post-transcriptional repression of expression of tumor suppressors, such as PTEN. This study was conducted to evaluate the significance of PTEN expression in pulmonary neuroendocrine (NE) tumors and to analyze the relationship between PTEN and miR-21 expressions.

Methods

Expressions of PTEN and miR-21 were investigated by immunohistochemistry and real time reverse transcription-polymerase chain reaction, respectively, in 75 resected pulmonary NE tumors (23 typical carcinoids [TCs], nine atypical carcinoids [ACs], 22 large cell NE carcinomas [LCNECs], and 21 small cell lung carcinomas [SCLCs]).

Results

Loss of PTEN expression was observed in four of 23 TCs (17.4%), four of nine ACs (44.4%), 16 of 22 LCNECs (72.7%) and nine of 21 SCLCs (42.9%) (p=.025). The expression level of miR-21 was significantly higher in high-grade NE carcinomas than in carcinoid tumors (p<.001). PTEN expression was inversely correlated with miR-21 expression (p<.001).

Conclusions

This study suggests that aberrant expression of PTEN in relation to miR-21 may represent an important step in the development and progression of pulmonary NE tumors.

Gene and isoform expression signatures associated with tumor stage in kidney renal clear cell carcinoma

Background

Identification of expression alternations between early and late stage cancers is helpful for understanding cancer development and progression. Much research has been done focusing on stage-dependent gene expression profiles. In contrast, relatively fewer studies on isoform expression profiles have been performed due to the difficulty of quantification and noisy splicing. Here we conducted both gene- and isoform-level analysis on RNA-seq data of 234 stage I and 81 stage IV kidney renal clear cell carcinoma patients, aiming to uncover the stage-dependent expression signatures and investigate the advantage of isoform expression profiling for identifying advanced stage cancers and predicting clinical outcome.

Results

Both gene and isoform expression signatures are useful for distinguishing cancer stages. They provide common and unique information associated with cancer progression and metastasis. Combining gene and isoform signatures even improves the classification performance and reveals additional important biological processes, such as angiogenesis and TGF−beta signaling pathway. Moreover, expression abundance of a number of genes and isoforms is predictive of the risk of cancer death in an independent dataset, such as gene and isoform expression of ITPKA, the expression of a functional important isoform of UPS19.

Conclusion

Isoform expression profiling provides unique and important information which cannot be detected by gene expression profiles. Combining gene and isoform expression signatures helps to identify advanced stage cancers, predict clinical outcome, and present a comprehensive view of cancer development and progression.

Therapeutic targets associated to E-cadherin dysfunction in gastric cancer

INTRODUCTION

Epithelial cadherin (E-cadherin) plays a key role in epithelial cell-cell adhesion, contributing to tissue differentiation and homeostasis. Throughout the past decades, research has shed light on the molecular mechanisms underlying E-cadherin's role in tumor progression, namely in invasion and metastization. Emerging evidence established E-cadherin as a tumor suppressor and suggests that targeting E-cadherin or downstream signaling molecules may constitute effective cancer therapeutics.

AREAS COVERED

This review aims to cover E-cadherin-mediated signaling during cancer development and progression and highlight putative therapeutic targets.

EXPERT OPINION

Reconstitution of E-cadherin expression or targeting of E-cadherin downstream molecules holds promise in cancer therapies. Considering the high frequency of CDH1 promoter hypermethylation as a second hit in malignant lesions from hereditary diffuse gastric cancer patients, histone deacetylase inhibitors are potential therapeutic agents in combination with conventional chemotherapy, specifically in initial tumor stages. Concerning E-cadherin-mediated signaling, we propose that HER receptors (as epidermal growth factor receptor) and Notch downstream targets are clinically relevant and should be considered in gastric cancer therapeutics and control.

High-expression of DJ-1 and loss of PTEN associated with tumor metastasis and correlated with poor prognosis of gastric carcinoma

BACKGROUND AND AIMS

DJ-1 and PTEN have been shown to involve in multiple cell processes and play an important role in cancer development and progression. However, their relationship with gastric carcinoma (GC) has not been identified yet. The purpose of this study is to clarify the relationship of DJ-1 and phosphatase and tensin homolog (PTEN) with clinicopathological parameters and prognosis in GC.

METHODS

114 specimens were collected from GC patients and expression of DJ-1 and PTEN in tissue microarray was evaluated by immunohistochemical staining. Correlation between immunostainings and clinicopathological parameters, follow-up data of patients, was analyzed statistically.

RESULTS

High expression of DJ-1 was found in 66.7% (76/114) and associated with tumor depth (P=0.003), lymph node metastasis (P=0.011), distant metastasis (P=0.001) and advanced clinical stage (P=0.001). Loss or downregulation of PTEN was found in 58.7% (67/114) and associated with advanced clinical stage (P=0.018) and high expression of DJ-1 in tumor cells (P=0.006). In univariate survival analysis, high-expression of DJ-1 or loss of PTEN was significantly associated with poor prognosis of GC patients. However, only tumor depth (P=0.011) and coexistence of DJ-1 and PTEN abnormal expression (P=0.009) emerged as strong independent prognostic factors for overall survival of GC patients.

CONCLUSIONS

the present study indicates that DJ-1 and PTEN may play their roles in progression of GC in a cooperating pattern. Co-existence of abnormal DJ-1 and PTEN expression is likely to serve as an independent predictive factor for prognosis of GC patients.