The Gene Expression Status of the PI3K/AKT/mTOR Pathway in Gastric Cancer Tissues and Cell Lines

LncRNA NORAD Promotes Proliferation And Inhibits Apoptosis Of Gastric Cancer By Regulating miR-214/Akt/mTOR Axis

PURPOSE

In previous studies, we confirmed that the overexpression of lncRNA NORAD was associated with the occurrence and development of gastric cancer (GC). The aim of the present study was to explore the molecular mechanism of lncRNA NORAD on GC cell proliferation and apoptosis in vitro and in vivo.

PATIENTS AND METHODS

The quantitative Real-Time PCR (qRT-PCR) was used to determine the expression levels of lncRNA NORAD and miR-214 in GC tissues and cells. The interaction between lncRNA NORAD and miR-214 was investigated by biological information and Dual-Luciferase gene reporter assay. Effect of lncRNA NORAD on GC tumor growth in vivo was studied in tumor xenograft model mice. The apoptosis of GC cells was determined by flow cytometry. The proliferation of GC cells was determined by 5-ethynyl-2´-deoxyuridine (EDU) and colony formation assays. Western Blot was used to determine the expressions of caspase-3, Akt and mTOR in GC tissues and cells.

RESULTS

The qRT-PCR results showed that lncRNA NORAD was highly expressed in human GC tissues and cell lines, while miR-214 was significantly down-regulated. Meanwhile, there was a direct interaction between lncRNA NORAD and miR-214. In addition, lncRNA NORAD could promote the growth and proliferation of GC cells both in vivo and in vitro. NOARD could also inhibit the apoptosis of GC cells by down-regulating caspase-3; however, miR-214 overexpression attenuated this effect. Moreover, lncRNA NORAD promoted the phosphorylation of Akt and mTOR in mouse GC tissues and GC cell lines, while miR-214 mimics inhibited that promotion.

CONCLUSION

These results suggested that NORAD could promote the development of GC by inhibiting miR-214 expression and activating the Akt/mTOR signaling pathway.

Immunofluorescence can assess the efficacy of mTOR pathway therapeutic agent Everolimus in breast cancer models

When breast cancer patients start to exhibit resistance to hormonal therapy or chemotherapy, the mTOR inhibitor everolimus can be considered as an alternative therapeutic agent. Everolimus can deregulate the PI3K/AKT/mTOR pathway and affect a range of cellular functions. In some patients, the agent does not exhibit the desired efficacy and, even worse, not without the associated side effects. This study assessed the use of immunofluorescence (IF) as a modality to fill this unmet need of predicting the efficacy of everolimus prior to administration. Cell viability and MTT assays based on IF intensities of pho-4EBP1 Thr37/46 and pho-S6K1 Ser424 on breast cancer cells (Hs578T, MCF7, BT474, MDA-MB-231) and patient-derived cell culture from metastatic sites (ABC-82T and ABC-16TX1) were interrogated. Results show that independent pho-4EBP1 Thr37/46 and pho-S6K1 Ser424 IF expressions can classify data into different groups: everolimus sensitive and resistant. The combined IF baseline intensity of these proteins is predictive of the efficacy of everolimus, and their intensities change dynamically when cells are resistant to everolimus. Furthermore, mTOR resistance is not only consequence of the AKT/mTOR pathway but also through the LKB1 or MAPK/ERK pathway. The LKB1 and pho-GSK3β may also be potential predictive markers for everolimus.

Identification of driver genes and key pathways of prolactinoma predicts the therapeutic effect of genipin

The purpose of the present study was to identify the potential targets and markers for diagnosis, therapy and prognosis in patients with prolactinoma at the molecular level and to determine the therapeutic effects of genipin in prolactinoma. The gene expression profiles of GSE2175, GSE26966 and GSE36314 were obtained from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) were identified after comparing between gene expression profiles of the prolactinoma tissues and normal tissues. Then, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and protein‑protein interaction (PPI) network analysis were conducted. In addition, in vitro, scratch assay, colony‑forming assay, Cell Counting Kit 8 (CCK8) assay and flow cytometry were performed to verify the functional effects of genipin. An aggregate of 12,695, 3,847 and 5,310 DEGs were identified from GSE2175, GSE26966 and GSE36314, respectively. The results of GO and KEGG analysis showed that the DEGs significant and important for prolactinoma were mostly involved with 'spindle pole' and 'oocyte meiosis'. A total of 20 genes were selected as hub genes with high degrees after PPI network analysis, including mitogen‑activated protein kinase 1 (MAPK1), MYC, early growth response 1 (EGR1), Bcl2 and calmodulin 1 (CALM1). CCK8 assay, colony‑forming assay and scratch assay were performed to verify the anti‑prolactinoma effect of genipin. The results of flow cytometry showed that apoptosis was increased by genipin. MAPK1, MYC, EGR1, Bcl2 and CALM1 were screened as main hub genes. Genipin upregulated the expression level of EGR1 and p21 (downstream mediator of EGR1) and EGR1, inhibited the proliferation and migration of prolactinoma cells. Genipin is a promising drug for treatment of patients with prolactinoma.

Sichong formula inhibits the proliferation and migration of human gastric cancer cells

Purpose

Traditional Chinese medicine (TCM) has gained increasing attention for the treatment of multiple chronic diseases, such as cancer. Here we aim to identify the antitumor activity of Sichong formula, a novel TCM, in human gastric cancer cells and investigate the underlying mechanisms.

Methods

The AGS and MKN45 gastric cancer cells were treated with Sichong formula at different concentrations. The proliferation rates were tested by CCK-8 and colony formation assays. Cell migration and invasion were tested by scratch and transwell assays. Gelatin zymography was used to detect the matrix metalloproteinase 9 (MMP9) activity in cell suspendents. Cell apoptosis was analyzed by Annexin V/PI staining and flow cytometry. The expression of interest proteins was tested by Western blot.

Results

Cell proliferation analysis indicated that Sichong formula inhibited cell viability of AGS and MKN45 cells in a dose- and time-dependent manner. The IC50 values were 240 μg/mL and 200 μg/mL for AGS and MKN45 cells, respectively. Furthermore, we found that Sichong formula could inhibit the invasion and migration of gastric cancer cells, which might be mediated by the downregulation of MMP9 activity. Flow cytometry results indicated that Sichong formula induced apoptosis in gastric cancer cells through upregulation of Bax/Bcl2 ratio and activation of caspase cascade. The results from Western blot indicated that Sichong formula resulted in cell autophagy and inactivation of AKT signaling pathway.

Conclusion

Our data suggest that Sichong formula inhibits the proliferation and migration and induces apoptosis in human gastric cancer cells. The inhibitory effect of Sichong formula was, at least partly, mediated by cell autophagy and AKT pathway.

E2F6-mediated lncRNA CASC2 down-regulation predicts poor prognosis and promotes progression in gastric carcinoma

AIMS

To investigate the potential biological role of E2F6 and its underlying molecular mechanism in gastric carcinoma (GC) progression.

MAIN METHODS

The expressions of cancer susceptibility candidate 2 (CASC2), E2F6 and matrix metalloprotein-2 (MMP-2) were measured by quantitative real-time polymerase chain reaction and western blotting. The inhibitory effect of E2F6 on CASC2 was evaluated using luciferase reporter assay. Cell growth was assessed by colony formation assay and cell counting kit-8. Cell invasion and apoptosis were measured by transwell assay and flow cytometry assay, respectively. In vivo tumorigenicity was assessed by tumor xenografts in nude mice.

KEY FINDINGS

Our data revealed that CASC2 was downregulated while E2F6 was upregulated in GC tissues and cell lines. Remarkably, lower expression of CASC2 was associated with poor survival in GC patients. E2F6 inhibited the expression of CASC2. Subsequently, reliable data showed that downregulation of E2F6 suppressed the proliferation and invasion, and promoted the apoptosis of GC cells. Furthermore, downregulation of E2F6 decreased the expression of MMP-2 and increased the activity of caspase-3. However, these changes triggered by E2F6 knockdown could be reversed by inhibition of CASC2. Moreover, we also proved that downregulation of CASC2 reverses the effect of E2F6 knockdown on tumor growth in vivo.

SIGNIFICANCE

Our data demonstrated that E2F6 could regulate the proliferation, invasion and apoptosis of GC cells via inhibiting the expression of CASC2, suggesting that E2F6/CASC2 axis is another regulator of GC progression.

hsa_circ_0006168 sponges miR-100 and regulates mTOR to promote the proliferation, migration and invasion of esophageal squamous cell carcinoma

Circle RNAs (circRNAs) are the novel noncoding RNAs with the covalent closed-loop structure, which play a crucial role in a variety of pathological processes, including cancer. Nevertheless, the expression profiles and functions of circRNAs in esophageal squamous cell cancer (ESCC) remain largely unknown. In this paper, 10 pairs of ESCC tissues were utilized to screen the circRNA expression profiles by means of microarray assay; further, a novel circular RNA named hsa_circ_0006168 was investigated. Meanwhile, the expression of hsa_circ_0006168 was measured in 52 ESCC tissues and in cell lines. Our results suggested that, hsa_circ_0006168 was remarkably increased not only in ESCC tissues but also in cell lines compared with those in normal cases. Besides, high hsa_circ_0006168 expression was positively connected with lymph node metastasis and TNM stage of ESCC patients. In vitro, the proliferation, invasion and migration capacities of ESCC cells were suppressed through down-regulating hsa_circ_0006168 expression. Besides, RNase R digestion assay confirmed that hsa_circ_0006168 was more stable than its linear CNOT6L mRNA form. Moreover, nuclear and cytoplasmic fraction assay indicated that hsa_circ_0006168 was mainly distributed in the cytoplasm of Kyse450 and TE13 cells. Mechanically, it was discovered in this study that hsa_circ_0006168 might regulate the expression of Mammalian Target of Rapamycin (mTOR) by sponging microRNA-100 (miR-100). Taken together, hsa_circ_0006168 can promote ESCC proliferation, migration and invasion through the competing endogenous RNA (ceRNA) mechanism, which has been first confirmed in our results. In ESCC, hsa_circ_0006168 can serve as a potential diagnostic biomarker and therapeutic target.

Serine Protease from Nereis virens Inhibits H1299 Lung Cancer Cell Proliferation via the PI3K/AKT/mTOR Pathway

This study explores the in vitro anti-proliferative mechanism between Nereis Active Protease (NAP) and human lung cancer H1299 cells. Colony formation and migration of cells were significantly lowered, following NAP treatment. Flow cytometry results suggested that NAP-induced growth inhibition of H1299 cells is linked to apoptosis, and that NAP can arrest the cells at the G0/G1 phase. The ERK/MAPK and PI3K/AKT/mTOR pathways were selected for their RNA transcripts, and their roles in the anti-proliferative mechanism of NAP were studied using Western blots. Our results suggested that NAP led to the downregulation of p-ERK (Thr 202/Tyr 204), p-AKT (Ser 473), p-PI3K (p85), and p-mTOR (Ser 2448), suggesting that NAP-induced H1299 cell apoptosis occurs via the PI3K/AKT/mTOR pathway. Furthermore, specific inhibitors LY294002 and PD98059 were used to inhibit these two pathways. The effect of NAP on the downregulation of p-ERK and p-AKT was enhanced by the LY294002 (a PI3K inhibitor), while the inhibitor PD98059 had no obvious effect. Overall, the results suggested that NAP exhibits antiproliferative activity by inducing apoptosis, through the inhibition of the PI3K/AKT/mTOR pathway.

Use of phthalate-containing prescription drugs and the risk of gastric cancer: a Danish nationwide case-control study

Background: Phthalates are used as excipients in some drug products, and up to a 50-fold increased urinary excretion of phthalate metabolites compared to non-users has been demonstrated in users of such products. In vitro studies have demonstrated that phthalates stimulate mechanisms involved in gastric cancer development. We therefore examined the association between cumulative phthalate exposure from drug products and the risk of gastric adenocarcinomas. Methods: Using the Danish Cancer Registry, we identified all patients with incident gastric adenocarcinoma from 2008 to 2015 (n = 1525). Cancer cases were matched to 10 controls. Linking information retrieved from nationwide Danish registries, we determined individual cumulative phthalate exposure to the ortho-phthalates diethyl phthalate (DEP), dibutyl phthalate (DBP) and enteric phthalate polymers from prescription drugs. The association between cumulative phthalate exposure and gastric adenocarcinoma was estimated using conditional logistic regression, adjusting for socioeconomical status and drugs or comorbidities known or suspected to modify the risk of gastric adenocarcinoma. Results: No association was seen for the risk of gastric adenocarcinomas among individuals with high cumulative exposure to ortho-phthalates (exceeding 500 mg) (OR_adj 1.22, 95% CI: 0.84-1.77). Likewise, no associations were observed individually for DEP (OR_adj 1.06 95% CI: 0.63-1.76) or DBP (OR_adj 1.32 95% CI: 0.78-2.23). Cumulative exposure to enteric phthalate polymers exceeding 10,000 mg, did not reveal an association with gastric adenocarcinoma (OR_adj 0.79, 95% CI: 0.54-1.16) and no association was seen for individual compounds. Additionally, no dose-response pattern was observed across exposure strata (p = .39, test for trend). Conclusion: We did not find an increased risk of gastric adenocarcinoma among Danish users of phthalate-containing drug products. Our study is limited by a low number of cases exposed to high cumulative doses of phthalates.

Ubenimex Reverses MDR in Gastric Cancer Cells by Activating Caspase-3-Mediated Apoptosis and Suppressing the Expression of Membrane Transport Proteins

Gastric cancer (GC) is one of the most malignant tumors, accounting for 10% of deaths caused by all cancers. Chemotherapy is often necessary for treatment of GC; the FOLFOX regimen is extensively applied. However, multidrug resistance (MDR) of GC cells prevents wider application of this treatment. Ubenimex, an inhibitor of CD13, is used as an immune adjuvant to treat hematological malignancies. Here, we demonstrate that CD13 expression positively correlates with MDR development in GC cells. Moreover, Ubenimex reverses the MDR of SGC7901/X and MKN45/X cells and enhances their sensitivity to FOLFOX, in part by decreasing CD13 expression, which is accompanied by downregulation of Bcl-xl, Bcl-2, and survivin expression; increased expression of Bax; and activation of the caspase-3-mediated apoptotic cascade. In addition, Ubenimex downregulates expression of membrane transport proteins, such as P-gp and MRP1, by inhibiting phosphorylation in the PI3K/AKT/mTOR pathway to increase intracellular accumulations of 5-fluorouracil and oxaliplatin, a process for which downregulation of CD13 expression is essential. Therefore, the present results reveal a previously uncharacterized function of CD13 in promoting MDR development in GC cells and suggest that Ubenimex is a candidate for reversing the MDR of GC cells.

mTOR Signaling in Cancer and mTOR Inhibitors in Solid Tumor Targeting Therapy

The mammalian or mechanistic target of rapamycin (mTOR) pathway plays a crucial role in regulation of cell survival, metabolism, growth and protein synthesis in response to upstream signals in both normal physiological and pathological conditions, especially in cancer. Aberrant mTOR signaling resulting from genetic alterations from different levels of the signal cascade is commonly observed in various types of cancers. Upon hyperactivation, mTOR signaling promotes cell proliferation and metabolism that contribute to tumor initiation and progression. In addition, mTOR also negatively regulates autophagy via different ways. We discuss mTOR signaling and its key upstream and downstream factors, the specific genetic changes in the mTOR pathway and the inhibitors of mTOR applied as therapeutic strategies in eight solid tumors. Although monotherapy and combination therapy with mTOR inhibitors have been extensively applied in preclinical and clinical trials in various cancer types, innovative therapies with better efficacy and less drug resistance are still in great need, and new biomarkers and deep sequencing technologies will facilitate these mTOR targeting drugs benefit the cancer patients in personalized therapy.

Comprehensive profiling of JMJD3 in gastric cancer and its influence on patient survival

Histone methylation is thought to control the regulation of genetic program and the dysregulation of it has been found to be closely associated with cancer. JMJD3 has been identified as an H3K27 demethylase and its role in cancer development is context specific. The role of JMJD3 in gastric cancer (GC) has not been examined. In this study, JMJD3 expression was determined. The prognostic significance of JMJD3 and its association with clinical parameters were evaluated. JMJD3 dysregulation mechanism and targets were analyzed. The effect of JMJD3 mutation was determined by functional study. Results showed that JMJD3 was overexpressed in different patient cohorts and also by bioinformatics analysis. High JMJD3 expression was correlated with shortened overall survival in patients with GC and was an independent prognosis predictor. Genetic aberration and DNA methylation might be involved in the deregulation of JMJD3 in GC. Downstream network of JMJD3 was analyzed and several novel potential targets were identified. Furthermore, functional study discovered that both demethylase-dependent and demethylase-independent mechanisms were involved in the oncogenic role of JMJD3 in GC. Importantly, histone demethylase inhibitor GSK-J4 could reverse the oncogenic effect of JMJD3 overexpression. In conclusion, our study report the oncogenic role of JMJD3 in GC for the first time. JMJD3 might serve as an important epigenetic therapeutic target and/or prognostic predictor in GC.

Hypermethylation of EIF4E promoter is associated with early onset of gastric cancer

Although gastric cancer (GC) in young adults (≤ 45 years) accounts for fewer than 10% of newly diagnosed cases, the young patients are more likely to have advanced disease at presentation compared with elderly patients. Previous studies have identified that the DNA methylation of genomes are different during aging. Our study aimed to explore the association between DNA methylation and the onset of GC. We applied Illumina HumanMethylation450 BeadChip to examine methylation expression profiles and compared methylation expression patterns in five early onset GC patients and seven elderly patients. Additionally, we evaluated the associations of methylation expression with different clinicopathological characteristics of GC. Our results showed that the pattern of genome-wide methylation expression was significantly different between early onset and elderly GC. The top 10 hypomethylation and hypermethylation CpG sites were selected for further analyses in The Cancer Genome Atlas (TCGA) database. We found that the hypermethylation of cg11037477, located at the promoter of EIF4E, was significantly associated with age at diagnosis and the expression of EIF4E. Besides, GC patients with high level of cg11037477 were more likely to have advance disease with T3/T4 invasion and III/IV stage. The cg11037477 hypermethylation and EIF4E down-expression were significantly related to poor survival of GC patients. Our study provides new insights into the molecular mechanism of early onset patients with GC and suggests that methylation of cg11037477 and expression of EIF4E may act as prognostic markers in GC.

KT2 and RT2 modified antimicrobial peptides derived from Crocodylus siamensis Leucrocin I show activity against human colon cancer HCT-116 cells

Conventional colon cancer treatments have been associated with side effects. Consequently, the discovery of novel effective and safe therapies is urgently needed. Hence, cationic antimicrobial peptides KT2 and RT2 were evaluated towards human colon cancer HCT-116 cells. The MTT assay indicated that both KT2 and RT2 exhibited anticancer activity with good therapeutic indices, and were found to be non-toxic to non-cancerous Vero cells. The IC₅₀ values of KT2 were determined as 111.96 and 90.25 μg/mL while RT2 showed IC₅₀ as 104.07 and 87.84 μg/mL after 12 and 24 h treatments, respectively. Moreover, KT2 and RT2 treatment caused a significant reduction in PI3K, AKT1 and mTOR mRNA expression levels, which resulted in suppression either of HCT-116 proliferation or migration. The mechanism involved in apoptosis induction were due to decreased Bcl-2 and XIAP and increased p53, cytochrome c, caspase-2, caspase-3, caspase-8, and caspase-9 mRNA expression levels. These effects increased the level of cell cycle associated gene p21 and decreased cyclin B1 and cyclin D1 expression.

Long Noncoding RNA ATB Promotes Proliferation, Migration, and Invasion in Bladder Cancer by Suppressing MicroRNA-126

This study aimed to explore the biological functions of long noncoding RNA activated by transforming growth factor-β (lncRNA-ATB) in bladder cancer cells. For the expressions of lncRNA-ATB, miR-126, and KRAS, T24 cells were transfected with their specific vectors/shRNA or mimic/inhibitor. Then cell viability, migration, invasion, and apoptosis as well as the protein levels of apoptosis-related factors and PI3K/AKT and mTOR signal pathways were measured. The relationships of lncRNA-ATB and miR-126 or miR-126 and KRAS were analyzed by Dual-Luciferase Reporter assay. Functional experiments showed that lncRNA-ATB overexpression significantly promoted cell viability, migration, and invasion in T24 cells. lncRNA-ATB was a molecular sponge of miR-126 and exerted tumor-promoting effects by downregulation of miR-126. Moreover, KRAS was a direct target of miR-126 and was negatively regulated by miR-126. Finally, overexpression of KRAS increased cell viability, migration, and invasion, as well as activated PI3K/AKT and mTOR signaling pathways in T24 cells. The results revealed that lncRNA-ATB was an oncogene, which promoted cell proliferation, migration, and invasion by regulating miR-126 in bladder cancer. These findings may provide a potential prognostic biomarker and a therapeutic target for bladder cancer.

Anticancer effect of resibufogenin on gastric carcinoma cells through the phosphoinositide 3-kinase/protein kinase B/glycogen synthase kinase 3β signaling pathway

The aim of the present study was to investigate the anticancer effect of resibufogenin in gastric carcinoma cells through the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/glycogen synthase kinase 3β (GSK3β) signaling pathway. MGC-803 cells were treated with 0, 1, 2, 4 and 8 µM resibufogenin for 12, 24 and 48 h. Cell viability and apoptosis were measured using an MTT assay and annexin V staining. Caspase-3 and caspase-8 activity were identified using caspase-3 and caspase-8 activity kits and a variety of protein expression [B cell lymphoma (Bcl)-2, Bcl-2-associated X protein (Bax), cyclin D1, cyclin E, PI3K, phosphorylated AKT, phosphorylated GSK3β and β-catenin] were quantified using western blot analysis. It was revealed that resibufogenin effectively inhibited cell proliferation, and induced apoptosis and caspase-3 and caspase-8 activity in MGC-803 cells. Furthermore, treatment with resibufogenin effectively increased Bax/Bcl-2 expression, and suppressed cyclin D1, cyclin E, PI3K, phosphorylated AKT, phosphorylated GSK3β and β-catenin protein expression in MGC-803 cells. These results suggest that the anticancer effect of resibufogenin induces gastric carcinoma cell death through the PI3K/AKT/GSK3β signaling pathway, offering a novel view of the mechanism by which resibufogenin functions as an agent to treat gastric carcinoma.

Gastrin inhibits gastric cancer progression through activating the ERK-P65-miR23a/27a/24 axis

BACKGROUND

To test the hypothesis that activated extracellular signal-regulated kinase (ERK) regulates P65-miR23a/27a/24 axis in gastric cancer (GC) and the ERK-P65-miR23a/27a/24 axis plays an important role in the development of GC, and to evaluate the role of gastrin in GC progression and ERK-P65-miR23a/27a/24 axis.

METHODS

The component levels of the ERK-P65-miR23a/27a/24 axis in four fresh GC tissues, 101 paraffin-embedded GC tissues and four GC cell lines were determined by Western blotting, immunohistochemistry (IHC) or qRT-PCR. The effects of gastrin on GC were first evaluated by measuring gastrin serum levels in 30 healthy and 70 GC patients and performing a correlation analysis between gastrin levels and survival time in 27 GC patients after eight years of follow-up, then evaluated on GC cell lines, GC cell xenograft models, and patient-derived xenografts (PDX) mouse models. The roles of ERK-P65-miR23a/27a/24 axis in GC progression and in the effects of gastrin on GC were examined.

RESULTS

ERK- P65-miR23a/27a/24 axis was proved to be present in GC cells. The levels of components of ERK-P65-miR23a/27a/24 axis were decreased in GC tissue samples and PGC cells. The decreased levels of components of ERK-P65-miR23a/27a/24 axis were associated with poor prognosis of GC, and ERK-P65-miR23a/27a/24 axis played a suppressive role in GC progression. Low blood gastrin was correlated with poor prognosis of the GC patients and decreased expression of p-ERK and p-P65 in GC tissues. Gastrin inhibited proliferation of poorly-differentiated GC (PGC) cells through activating the ERK-P65-miR23a/27a/24 axis. Gastrin inhibited GC growth and enhanced the suppression of GC by cisplatin in mice or PGC cell culture models through activating the ERK-P65-miR23a/27a/24 axis or its components.

CONCLUSIONS

ERK-P65-miR23a/27a/24 axis is down-regulated, leading to excess GC growth and poor prognosis of GC. Low gastrin promoted excess GC growth and contributed to the poor prognosis of the GC patients by down-regulating ERK-P65-miR23a/27a/24 axis. Gastrin inhibits gastric cancer growth through activating the ERK-P65-miR23a/27a/24 axis.

Inhibitory effects of CP on the growth of human gastric adenocarcinoma BGC-823 tumours in nude mice

Objective

To investigate the potential antitumour effects of [2-(6-amino-purine-9-yl)-1-hydroxy-phosphine acyl ethyl] phosphonic acid (CP) against gastric adenocarcinoma.

Methods

Human BGC-823 xenotransplants were established in nude mice. Animals were randomly divided into control and CP groups, which were administered NaHCO₃ vehicle alone or CP dissolved in NaHCO₃ (200 µg/kg body weight) daily, respectively. Tumour volume was measured weekly for 6 weeks. Resected tumours were assayed for proliferative activity with anti-Ki-67 or anti-proliferating cell nuclear antigen (PCNA) antibodies. Cell apoptosis was examined using terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) assays and with caspase-3 immunostaining. Proteins were measured by Western blotting.

Results

There was a significant reduction in tumour volume and a reduced percentage of Ki-67-positive or PCNA-positive cells in the CP group compared with the control group. The percentage of TUNEL-positive or caspase 3-positive cells significantly increased following CP treatment compared with the control group. Tumours from the CP group had higher levels of phosphorylated-extracellular signal-regulated kinase (p-ERK) and phosphorylated-AKT (p-AKT) compared with control tumours.

Conclusion

CP treatment inhibited tumour growth and induced tumour cell apoptosis in a nude mouse model of BGC-823 gastric adenocarcinoma. Activation of the AKT and ERK signalling pathways may mediate this antitumour activity.

LY294002 inhibits the Warburg effect in gastric cancer cells by downregulating pyruvate kinase M2

The ‘Warburg effect’ is considered a vital hallmark of cancer cells, characterized by an altered metabolism, in which cells rely on aerobic glycolysis. As a key enzyme of aerobic glycolysis, pyruvate kinase M2 (PKM2) serves a crucial role in tumorigenesis. Accumulating studies have indicated that PKM2 is a potential target for cancer therapy. The aim of the present study was to assess the anticancer effects of LY294002, a specific phosphatidylinositol-3-kinase inhibitor, on gastric cancer (GC) cells and further explore its possible mechanism in vitro. The present study revealed that LY294002 inhibited GC cell proliferation, induced early apoptosis and significantly decreased lactate dehydrogenase activity and lactate production, in part through inhibiting PKM2 expression. In summary, LY294002 exhibits anticancer effects on GC, partly via the downregulation of PKM2.

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.

Gastric cancer management: Kinases as a target therapy

The molecular diagnostics revolution has reshaped the practice of oncology by facilitating the identification of genetic, epigenetic and proteomic modifications correlated with cancer, thus delineating 'oncomaps' for various cancer types. These advances have enhanced our understanding of gastric cancer, one of the most fatal diseases worldwide, and culminated in the approval of novel molecular therapies such as trastuzumab. Gastric tumours display recurrent aberrations in key kinase oncogenes such as Her2, epidermal growth factor receptor (EGFR), PI3K, mTOR or c-Met, suggesting that these receptors are amenable to inhibition using specific drug agents. In this review, we examine the mutational landscape of gastric cancer, the use of kinase inhibitors as targeted therapies in gastric tumours and the clinical trials underway for novel inhibitors, highlighting successes, failures and future directions.

Upregulation of long noncoding RNA LOC440040 promotes tumor progression and predicts poor prognosis in patients with prostate cancer

Background/purpose

Long noncoding RNAs (lncRNAs) play a functional role in the initiation and progression of prostate cancer (PCa). This study aimed to determine differentially expressed lncRNA through high-throughput sequencing technology and investigate its expression, biological function and clinical correlation with PCa.

Materials and methods

Candidate lncRNAs were identified through microarray screening and bioanalysis. The expression of lncRNA LOC440040 in PCa tissues and cell lines was determined by reverse-transcription polymerase chain reaction. The relationship between LOC440040 level and clinicopathological characteristics was analyzed by paired t-test or chi-square test, and its association with patient prognosis was assessed by the Kaplan–Meier method. The effects of LOC440040 on PC-3 and 22RV1 cells were evaluated by Cell Counting Kit-8 (CCK-8), migration, invasion and colony formation assays.

Results

LOC440040 expression was upregulated in PCa tissues and cell lines. Clinicopathological analysis showed that patients with high LOC440040 expression exhibited more advanced clinical features and shorter overall survival than those with low LOC440040 expression. Multivariate regression analysis revealed that LOC440040 expression was an independent prognostic factor in patients with PCa. Knockdown of LOC440040 inhibited PCa cell proliferation, migration and invasion.

Conclusion

LOC440040 may play an oncogenic role in PCa initiation and progression. This lncRNA could be a novel molecular prognostic biomarker and a potential therapeutic target for PCa.

Phosphorylated Mammalian Target of Rapamycin p-mTOR Is a Favorable Prognostic Factor than mTOR in Gastric Cancer

Aims

The mammalian target of rapamycin (mTOR) and phosphorylated mTOR (p-mTOR) occurring downstream in the PI3K/Akt/mTOR pathway, are regarded as potential prognostic markers for gastric cancer (GC). However, the prognostic value of mTOR/p-mTOR expression remains controversial. In this study, we determined the expression of mTOR, p-mTOR, p70S6k, and p-p70S6K in GC, and investigated the correlation between their overexpression, clinicopathological parameters, and overall survival (OS).

Methods

The expression of mTOR, p-mTOR, p70S6k, and p-p70S6K was examined in 120 GC patients by immunohistochemistry (IHC). The association of protein expression with clinicopathological features and OS was explored. The p-mTOR expression was detected in normal, adjacent, and GC tissues using Western blot. Eligible studies retrieved from PubMed, Ovid, Web of Science and Cochrane databases, were reviewed in this meta-analysis.

Results

IHC showed that the rates of expression of the signal transduction molecules mTOR, p-mTOR, p70S6k and p-p70S6K in GC were 60.8%, 54.2%, 53.3% and 53.3%, respectively. Overexpression of mTOR and p70S6K showed no significant association with clinical variables. Expression of p-mTOR was significantly associated with differentiation (P < 0.01), depth of invasion (P < 0.01), lymph node metastasis (P = 0.04) and TNM stage (P = 0.02). Expression of p-p70S6K was associated with differentiation (P = 0.006), depth of invasion (P < 0.001), and TNM stage (P = 0.02). In survival analysis, differentiation, depth of invasion, lymph node metastasis and TNM stage were not related to OS (all P > 0.05). Furthermore, p-mTOR and p-p70S6K expression, but not mTOR and p70S6K, were tightly associated with OS of GC patients (P = 0.006 and P < 0.001, respectively). In Western blot, p-mTOR was significantly higher in GC tissues than in normal and adjacent tissues. In the present meta-analysis, mTOR overexpression showed no relationship with any clinicopathological variables. However, p-mTOR was correlated with depth of invasion, and TNM stage (all P < 0.05), and its overexpression was associated with a shorter survival time (P < 0.001).

Conclusion

The results suggest that p-mTOR is a more valuable prognostic factor than mTOR in GC.

Valproic acid induces autophagy by suppressing the Akt/mTOR pathway in human prostate cancer cells

Previous studies have demonstrated that the chronic administration of valproic acid (VPA) suppresses angiogenesis in vivo; however, the mechanisms implicated in VPA-induced autophagy remain unclear. The current study aimed to assess VPA-induced autophagy in three prostate cancer cell lines (PC3, DU145 and LNCaP), in addition to analyzing the Akt/mammalian target of rapamycin (mTOR) signal pathway. Prostate cancer cell lines were cultured with various doses of VPA. Cell cycle was analyzed using flow cytometry, and autophagy markers [1A/1B-light chain 3 (LC3)-II and Beclin-1] were examined using transmission electron microscopy, fluorescent microscopy and western blotting. Activation of the Akt/mTOR signal pathway was also assessed by western blotting. The results demonstrated that VPA induced autophagosomes and suppressed the Akt/mTOR signal pathway. This was confirmed by detection of increased LC3-II and Beclin-1 in VPA-treated cells compared with untreated controls. Phosphorylated forms of Akt (PC3, P=0.048; DU145, P=0.045; LNCaP, P=0.039) and mTOR (PC3, P=0.012; DU145, P=0.41; LNCaP, P=0.35) were significantly reduced following VPA treatment. These results suggest that VPA may function as a histone deacetylase inhibitor, suppressing the growth of prostate cancer cells by modulating autophagy pathways, including inhibition of the Akt/mTOR pathway. Further experiments are required to determine the significance of all involved pathways regarding VPA-induced growth inhibition.