MDA19, a novel CB2 agonist, inhibits hepatocellular carcinoma partly through inactivation of AKT signaling pathway

Background

CB₂ (cannabinoid receptor 2) agonists have been shown to exert anti-tumor activities in different tumor types. However, there is no study exploring the role of MDA19 (a novel CB₂ agonist) in tumors. In this study we aimed to investigate the effects of MDA19 treatment on HCC cell lines, Hep3B and HepG2 and determine the relevant mechanisms.

Results

Cell proliferation analysis, including CCK8 and colony formation assays, indicated that MDA19 treatment inhibited HCC cell proliferation in a dose- and time-dependent manner. Flow cytometry suggested that MDA19 induced cell apoptosis and activation of mitochondrial apoptosis pathway. Transwell assay indicated that HCC cell migration and invasion were significantly inhibited by MDA19 treatment. Mechanism investigation suggested that MDA19 induced inactivation of AKT signaling pathway in HCC cells. In addition, we investigated the function of CB₂receptor in HCC and its role in the anti-tumor activity of MDA19. By searching on Kaplan-Meier plotter (http://kmplot.com/analysis/), we found that HCC patients with high CB₂ expression had a better survival and CB2 expression was significantly associated with gender, clinical stages and race of HCC patients (P < 0.05). CB₂ inhibited the progression of HCC cells and its knockdown could rescue the growth inhibition induced by MDA19 in HCC. Moreover, the inhibitory effect of MDA19 on AKT signaling pathway was also reversed by CB₂ knockdown.

Conclusion

Our data suggest that MDA-19 exerts an anti-tumor activity at least partly through inactivation of AKT signaling pathway in HCC. CB₂ functions as a tumor suppressor gene in HCC, and MDA19-induced growth inhibition of HCC cells depends on its binding to CB₂ to activate it. MDA-19 treatment may be a promising strategy for HCC therapy.

Reviewer

This article was reviewed by Tito Cali, Mohamed Naguib and Bo Chen.

Downregulation of microRNA-200c-3p reduces damage of hippocampal neurons in epileptic rats by upregulating expression of RECK and inactivating the AKT signaling pathway

OBJECTIVE

The aim of this study is to investigate the role of mircoRNA-200c-3p (miR-200c-3p) on hippocampal neuron injury in epileptic rats through the regulation of the AKT signaling pathway by targeting RECK.

METHODS

The epilepsy rat model was induced by intraperitoneal injection of lithium chloride-pilocarpine. Successful modeled rats were injected with miR-200c-3p inhibitors, inhibitors NC, siRNA-negative control (NC) and RECK-siRNA. The astrocyte activation, levels of oxidative stress indexes, contents of inflammatory factors and the AKT signaling pathway-related proteins in hippocampus tissues were evaluated.

RESULTS

High expression of miR-200c-3p and low expression of RECK were found in the hippocampus tissues of epileptic rats. Downregulation of miR-200c-3p or upregulation of RECK decreased apoptosis of hippocampal neurons, expression of GFAP, content of MDA and increased the activities of GSH-Px and SOD, decreased expression of TNF-α, IL-1β and IL-6 as well as expression of p-PI3K/t-PI3K and p-Akt/t-Akt in hippocampus tissues of epileptic rats.

CONCLUSION

Our study provides evidence that downregulation of miR-200c-3p reduces damage of hippocampal neurons in epileptic rats by upregulating RECK and inactivating the AKT signaling pathway.

Silibinin ameliorates diabetic nephropathy via improving diabetic condition in the mice

Diabetic nephropathy (DN) is a major cause of end-stage renal disease and one of the most severe diabetic complications. However, there is lack of effective treatments for DN and the underlying mechanisms of the renal injury remain unclear. In current study, we evaluated the effects of silibinin on DN and further explored the underlying mechanisms. We administrated silibinin to db/db mice for 10 weeks. Then we monitored the diabetic metabolic parameters, kidney function, oxidative stress and AKT signaling pathway in db/db mice. Administration of silibinin to db/db mice improved diabetic condition, as evidenced by the decrease of body weight, HbAc1level and serum insulin level in db/db mice. Silibinin prevented kidney injury and attenuated oxidative stress in db/db mice. Silibinin activated AKT signaling pathway and decreased the levels of p-GSK-3β, Bax and cleaved caspase-3. Silibinin ameliorates diabetic nephropathy by activating the AKT signaling pathway.

Targeting TPX2 suppresses proliferation and promotes apoptosis via repression of the PI3k/AKT/P21 signaling pathway and activation of p53 pathway in breast cancer

Targeting protein for Xenopus kinesin-like protein 2 (TPX2) is a microtubule-associated protein required for mitosis and spindle assembly. Previous studies showed that TPX2 is overexpressed in various human cancers and promotes cancer progression. In this study, the differentially expressed genes including TPX2 were screened in GEO database for gene expression microarray of breast cancer. The TPX2 expression level was significantly increased in breast cancer cells and the breast malignant tissues compared with those controls. In vitro experiment further confirmed that knockdown of TPX2 by small hairpin RNA inhibited breast cancer cell proliferatio, migration, and induced cell apoptosis. TPX2 silencing decreased the expression of PI3K and extent of AKT phosphorylation, as well as increased expression of p53 and p21. Taken together, our findings indicate that TPX2 silencing negatively regulates the PI3K/AKT and activates p53 signaling pathway by which breast cancer cells proliferation were inhibited whereas cellulars apoptosis were accelerated, suggesting that TPX2 may be a potential target for anticancer therapy in breast cancer.

Activation of mammalian terget of rapamycin kinase and glycogen synthase kinase-3β accompanies abnormal accumulation of cholesterol in fibroblasts from Niemann-Pick type C patients

BACKGROUND

Niemann Pick type C (NPC) lysosomal disorder is linked to the disruption of cholesterol transport. Recent data suggest that the molecular background of this disease is more complex. It was found that accumulation of cholesterol and glycolipids in the late endosomal/lysosomal compartment of NPC1 cells may affect mitochondrial functions.

MATERIALS AND METHODS

In this study, primary skin fibroblasts derived from skin biopsies of two anonymous patients with NPC-carrying mutations in the NPC1 gene, characterized by a high total cholesterol content, as well as two healthy donors were used. The presence of signaling proteins in the whole cell lysates and mitochondrial fractions were examined by Western blotting assay.

RESULTS

In this report, we provide experimental evidence that in NPC1 cells, dysfunction of mitochondria and cellular metabolism, as reported by Wos et al in 2016, coexist with alterations in signal transduction pathways, such as the mammalian target of rapamycin, AKT, phosphoinositide-dependent protein kinase-1, glycogen synthase kinase-3 β, and Jun amino-terminal kinase, leading to abnormal cholesterol accumulation and distribution.

CONCLUSION

Differences in signal transduction between control and NPC1 cells may suggest that the latter cells experienced significant alterations in the complex molecular mechanisms that control cellular energy metabolism and vesicular transport.

TPX2 gene silencing inhibits cell proliferation and promotes apoptosis through negative regulation of AKT signaling pathway in ovarian cancer

Ovarian cancer (OC) is the leading cause of death from gynecological malignancy. Accumulated studies have revealed that targeting protein for Xklp2 (TPX2) was tightly associated with the development and progression of OC. The present study further determined a novel mechanism of TPX2 in OC via the AKT signaling pathway. The differentially expressed genes were screened in GEO database for gene expression microarray of OC. Bioinformatics was used to analyze the key differentially expressed genes in OC. We prepared CD133/1+ OC stem cells. Then cells were treated with TPX2-1 siRNA and perifcsine to explore the correlation of TPX2 and the AKT signaling pathway. We determined the expression of TPX2, AKT, Pl3 K, PTEN, caspase-3, Bax and Bcl-2 in OC cells. Cell proliferation, migration, invasion, and apoptosis rate were respectively measured using MTT and EdU assays, Transwell assay, Scratch test, and flow cytometry. Xenograft tumor in nude mice was used to determine the effect of TPX2 in OC cells in vitro. Initially, TPX2 overexpression was observed in OC, and TPX2 mediated the effect of the AKT signaling pathway in OC. TPX2 knockdown decreased expression of AKT, Pl3 K, and Bcl-2, and the extent of AKT phosphorylation, but increased expression of PTEN, Caspase-3, and Bax. Furthermore, TPX2 knockdown suppressed OC cell proliferation, migration and invasion, but promoted OC cell apoptosis. Taken together, TPX2 silencing negatively regulates the AKT signaling pathway by which OC cell proliferation was inhibited yet cell apoptosis was accelerated, suggesting a potential therapeutic approach to OC.

Assessment of the methods used to detect HER2-positive advanced extramammary Paget's disease

The human epidermal growth factor receptor 2 (HER2) is recognized as an oncogene as well as a therapeutic target in various cancers. Certain patients with advanced extramammary Paget's disease (EMPD) have also been reported to express HER2, which is therefore considered a therapeutic target for EMPD. However, an accurate methodology to determine HER2-positive EMPD has not been established. To assess the optimal methods for detection of HER2-positive EMPD, 73 EMPD samples were analyzed by immunohistochemical (IHC) staining, fluorescence in situ hybridization (FISH), and the HER2 testing algorithm for breast cancer of the American Society of Clinical Oncology/College of American Pathologists, which combined the results of IHC staining and FISH. The results showed discordance in the rate of positive IHC staining and FISH results. While 68.6% (24/35) of the metastatic samples showed equivocal or positive IHC staining, only 37.1% (13/35) were positive by FISH. To assess the accuracy of these methods, the degree of HER2 expression detected by each method was correlated with the staining profiles of activated downstream signaling pathways involving phosphorylated p44/42 MAPK (Thr202/Tyr204) (p-ERK1/2) and phosphorylated AKT (Ser473) (p-AKT). Among 16 lymph node metastasis samples, all HER2-positive samples as determined by the testing algorithm stained positively for both p-ERK1/2 and p-AKT. On the other hand, 10-14.3% of the samples determined by FISH or IHC showed negative staining for p-ERK1/2 and p-AKT. The results showed that combining the results of IHC and FISH according to the HER2 testing algorithm is a useful method for accurately evaluating HER2-positive EMPD.

Sevoflurane post-conditioning attenuates traumatic brain injury-induced neuronal apoptosis by promoting autophagy via the PI3K/AKT signaling pathway

Background

Sevoflurane post-conditioning exerts nerve-protective effects through inhibiting caspase-dependent neuronal apoptosis after a traumatic brain injury (TBI). Autophagy that is induced by the endoplasmic reticulum stress plays an important role in the secondary neurological dysfunction after a TBI. However, the relationship between autophagy and caspase-dependent apoptosis as well as the underlying nerve protection mechanism that occurs with sevoflurane post-conditioning following a TBI remains unclear.

Methods

The Feeney TBI model was used to induce brain injury in rats. Evaluation of the modified neurological severity scores, measurement of brain water content, Nissl staining, and terminal deoxynucleotidyl transferase dUTP nick end labeling assay were used to determine the neuroprotective effects of the sevoflurane post-conditioning. Both immunofluorescence and Western blot analyses were used to detect the expression of autophagy-related proteins microtubule-associated protein 1 light chain 3-II and Beclin-1, pro-apoptotic factors, as well as the activation of the phosphatidylinositide 3-kinase/protein kinase B (PI3K/AKT) signaling pathway within the lesioned cortex.

Results

Autophagy and neuronal apoptosis were activated in the lesioned cortex following the TBI. Sevoflurane post-conditioning enhanced early autophagy, suppressed neuronal apoptosis, and alleviated brain edema, which improved nerve function after a TBI (all P < 0.05). Sevoflurane post-conditioning induced the activation of PI3K/AKT signaling after the TBI (P < 0.05). The neuroprotective effects of sevoflurane post-conditioning were reversed through the autophagy inhibitor 3-methyladenine treatment.

Conclusion

Neuronal apoptosis and the activation of autophagy were involved in the secondary neurological injury following a TBI. Sevoflurane post-conditioning weakened the TBI-induced neuronal apoptosis by regulating autophagy via PI3K/AKT signaling.

Effects of MicroRNA-206 on Osteosarcoma Cell Proliferation, Apoptosis, Migration and Invasion by Targeting ANXA2 Through the AKT Signaling Pathway

BACKGROUND/AIMS

This study aimed to investigate the mechanism by which microRNA-206 (miR-206) affects the proliferation, apoptosis, migration and invasion of osteosarcoma (OS) cells by targeting ANXA2 via the AKT signaling pathway.

METHODS

A total of 132 OS tissues and 120 osteochondroma tissues were examined in this study. The targeting relationship between miR-206 and ANXA2 was verified with a dual-luciferase reporter assay. The miR-206 expression and ANXA2, AKT, PARP, FASN, Survivin, Bax, Mcl-1 and Bcl-1 mRNA and protein expression in the above two groups were examined by qRT-PCR and western blotting. The cultured OS cells were divided into 6 groups: a blank group, negative control (NC) group, miR-206 mimic group, miR-206 inhibitor group, si-ANXA2 group and miR-206 inhibitor + si-ANXA2 group. Cell cycle and apoptosis were assessed by flow cytometry, cell migration was examined with a wound-healing assay, and cell invasion was assessed with a Transwell assay. Pearson correlation analysis was used to determine the correlation between ANXA2 mRNA expression and miR-206 expression in OS.

RESULTS

OS tissues exhibited increased mRNA and protein expression of ANXA2, AKT, PARP, FASN, Survivin, Mcl-1 and Bcl-2; decreased miR-206 expression; and decreased Bax mRNA and protein expression. ANXA2 mRNA expression was strongly negatively correlated with miR-206 expression in OS. ANXA2 was found to be a miR-206 target gene. In the miR-206 mimic group and the si-ANXA2 group, the mRNA and protein expression of ANXA2, AKT, PARP, FASN, Survivin, Mcl-1 and Bcl-1 decreased markedly, cell proliferation was inhibited, apoptosis was promoted, higher cell growth in G1 phase and decreased growth in S phase was detected, and decreased cell migration and invasion were observed compared with those in the blank group.

CONCLUSION

The current results demonstrate that miR-206 overexpression inhibits OS cell proliferation, migration and invasion and promotes apoptosis through targeting ANXA2 by blocking the AKT signaling pathway.

PBX3 is associated with proliferation and poor prognosis in patients with cervical cancer

Pre-B-cell leukemia homeobox 3 (PBX3) is upregulated in various malignancies; however, the role of PBX3 in cervical cancer (CC) is unknown. The purpose of this study was to explore the expression characteristics, clinicopathological significance, and molecular biological function of PBX3 in CC. The expression levels of PBX3 were analyzed in CC cell lines and tumor specimens by real-time polymerase chain reaction (RT-PCR), Western blotting, and immunohistochemical staining. The clinicopathological characteristics associated with PBX3 expression were evaluated. An RNA interference approach was employed to suppress PBX3 expression in CC in vitro and in vivo, determine its role in cell proliferation and analyze its molecular function. We found that PBX3 expression was significantly upregulated in CC cell lines and clinical specimens compared with normal cells and adjacent nontumorous cervical tissues. PBX3 was an independent predictive factor of poor prognosis, and its expression was correlated with tumor diameter, pathological grading, lymph node metastasis, invasion depth, vascular invasion, and clinical stage of CC. Multivariate analysis suggested that PBX3 expression may represent an independent prognostic indicator of the survival of CC patients. CC patients with high PBX3 expression exhibited reduced overall survival compared with those with low PBX3 expression. Additionally, stable downregulation of PBX3 expression in CC cell lines suppressed cell proliferation and decreased p-AKT protein expression levels in vitro. Similarly, in vivo assays demonstrated that PBX3 downregulation in CC cells markedly inhibited tumor size and weight. Overall, we demonstrated that PBX3 can promote CC cell proliferation via the AKT signaling pathway and that it may serve as a prognostic marker. Our data indicate that inactivation of PBX3 may be an effective clinical treatment for CC.

Intravenous miR-144 inhibits tumor growth in diethylnitrosamine-induced hepatocellular carcinoma in mice

Previous in vitro studies have demonstrated that miR-144 inhibits hepatocellular carcinoma cell proliferation, invasion, and migration. We have shown that miR-144, injected intravenously, is taken up by the liver and induces endogenous hepatic synthesis of miR-144. We hypothesized that administered miR-144 has tumor-suppressive effects on liver tumor development in vivo. The effects of miR-144 on tumorigenesis and tumor growth were tested in a diethylnitrosamine-induced hepatocellular carcinoma mouse model. MiR-144 injection had no effect on body weight but significantly reduced diethylnitrosamine-induced liver enlargement compared with scrambled microRNA. MiR-144 had no effect on diethylnitrosamine-induced liver tumor number but reduced the tumor size above 50%, as evaluated by magnetic resonance imaging (scrambled microRNA 23.07 ± 5.67 vs miR-144 10.38 ± 2.62, p < 0.05) and histological analysis (scrambled microRNA 30.75 ± 5.41 vs miR-144 15.20 ± 3.41, p < 0.05). The levels of miR-144 was suppressed in tumor tissue compared with non-tumor tissue in all treatment groups (diethylnitrosamine-phosphate-buffered saline non-tumor 1.05 ± 0.09 vs tumor 0.54 ± 0.08, p < 0.01; diethylnitrosamine-scrambled microRNA non-tumor 1.23 ± 0.33 vs tumor 0.44 ± 0.10, p < 0.05; diethylnitrosamine-miR-144 non-tumor 54.72 ± 11.80 vs tumor 11.66 ± 2.75, p < 0.01), but injection of miR-144 greatly increased miR-144 levels both in tumor and non-tumor tissues. Mechanistic studies showed that miR-144 targets epidermal growth factor receptor and inhibits the downstream Src/AKT signaling pathway which has previously been implicated in hepatocellular carcinoma tumorigenesis. Exogenously delivered miR-144 may be a therapeutic strategy to suppress tumor growth in hepatocellular carcinoma.

Osmotin Protects H9c2 Cells from Simulated Ischemia-Reperfusion Injury through AdipoR1/PI3K/AKT Signaling Pathway

Objective: This study aimed to investigate the effect of osmotin on myocardial ischemia/reperfusion (I/R), as well as the underlying mechanisms.

Methods:In vitro I/R injury model was established on rat cardiac myoblast H9c2 cells by oxygen and glucose deprivation followed by reperfusion (OGD/R). Cells were administrated with osmotin, and transfected with small interfering RNAs (siRNAs) which specifically target adiponectin receptor 1 or 2 (AdipoR1/2). Besides, the cells were incubated with or without LY294002 as inhibitor of phosphatidylinositol 3-kinase (PI3K) under OGD/R condition. Cell viability, apoptosis, expressions of apoptosis-related proteins and inflammatory factors were analyzed.

Results: The results showed that osmotin significantly increased H9c2 cells viability compared with the cells treated with vehicle (P < 0.05), and decreased H9c2 cells apoptosis by regulating expressions of apoptosis-related proteins. Moreover, we observed that osmotin statistically reduced the release of proinflammatory factors and increased the release of anti-inflammatory factors in H9c2 cells (P < 0.05). However, these effects were markedly reversed by AdipoR1 silence but not AdipoR2. Furthermore, osmotin dramatically upregulated the phosphorylation levels of PI3K, AKT, ERK, and downregulated the phosphorylation level of NF-κB (P < 0.05). While administration of LY294002 reduced cell viability, increased cell apoptosis, and aggravated inflammatory response (P < 0.05).

Conclusion: Our results suggested that the protective effect of osmotin on the simulated OGD/R injured H9c2 cells might be associated with AdipoR1/PI3K/AKT signaling pathway.

Cellular inhibitor of apoptosis protein 2 promotes the epithelial-mesenchymal transition in triple-negative breast cancer cells through activation of the AKT signaling pathway

Triple-negative breast cancer (TNBC) represents approximately 10–17% of all breast cancers, and patients with TNBC show a poorer short-term prognosis than patients with other types of breast cancer. TNBCs also have a higher tendency for early distant metastasis and cancer recurrence due to induction of the epithelial-mesenchymal transition (EMT). Several recent reports have suggested that inhibitor of apoptosis (IAP) proteins function as regulators of the EMT. However, the roles of these proteins in TNBC are not clear. Accordingly, we investigated the roles of cIAP2 in TNBC. Among eight IAP genes, only cIAP2 was upregulated in TNBC cells compared with that in other breast cancer subtypes. Analysis of TMAs revealed that expression of cIAP2 was upregulated in TNBCs. In vitro studies showed that cIAP2 was highly expressed in TNBC cells compared with that in other types of breast cancer cells. Furthermore, silencing of cIAP2 in TNBC cells induced mesenchymal-epithelial transition (MET)-like processes and subsequently suppressed the migratory ability and invasion capacity of the cells by regulation of Snail through the AKT signaling pathway. In contrast, ectopic expression of cIAP2 in luminal-type breast cancer cells induced activation of the AKT signaling pathway. These results collectively indicated that cIAP2 regulated the EMT in TNBC via activation of the AKT signaling pathway, contributing to metastasis in TNBC. Our study proposes a novel mechanism through which cIAP2 regulates the EMT involving AKT signaling in TNBC cells. We suggest that cIAP2 may be an attractive candidate molecule for the development of targeted therapeutics in the future.

MicroRNA-302b-3p Suppresses Cell Proliferation Through AKT Pathway by Targeting IGF-1R in Human Gastric Cancer

BACKGROUND/AIMS

MiR-302b is a major microRNA found in human embryonic stem cells and induced pluripotent stem cells. However, its function in gastric cancer progression remains unclear.

METHODS

Quantitative reverse transcription-PCR was performed to detect the expression levels of miR-302b-3p in gastric cancer tissues. MTT, colony formation, and flow cytometer analyses were conducted to explore the function of miR-302b-3p in MKN-45/SGC-7901 cells. A dual-luciferase reporter was used to validate the bioinformatics-predicted target gene of miR-302b-3p. Western blotting and RNA interference were used to evaluate the expression of the AKT signaling pathway and determine the mechanisms underlying miR-302b-3p-induced anti-tumor effects.

RESULTS

MiR-302b-3p expression was decreased in gastric cancer tissues and cell lines. Enforced expression of miR-302b suppressed cell proliferation and cell cycle G1-S transition and induced apoptosis. IGF-1R was found to be a direct target of miR-302b-3p, and silencing of IGF-1R resulted in the same biological effects as those induced by miR-302b-3p overexpression in gastric cancer cells. Importantly, both overexpression of miR-302b-3p and silencing of IGF-1R decreased AKT phosphorylation, which modulated AKT related cell cycle regulators (cyclin A2, cyclin D1, CDK2, and CDk6) and apoptotic protein Bax/Bcl-2.

CONCLUSION

These results indicate the tumor suppressor role of miR-302b-3p in the pathogenesis of gastric cancer.

Urokinase-type plasminogen activator receptor promotes proliferation and invasion with reduced cisplatin sensitivity in malignant mesothelioma

Malignant mesothelioma (MM) is a rare neoplasm associated with asbestos exposure. The prognosis of MM is poor because it is aggressive and highly resistant to chemotherapy. Using a rat model of asbestos-induced MM, we found elevated urokinase-type plasminogen activator receptor (uPAR; Plaur) expression in rat tissues, which was associated with poor prognosis. The proliferation, migration and invasion of MM cells were suppressed by uPAR knockdown and increased by overexpression experiments, irrespective of urokinase-type plasminogen activator (uPA; Plau) levels. More importantly, we found that uPAR expression is associated with sensitivity to cisplatin in MM through the PI3K/AKT pathway, which was demonstrated with specific inhibitors, LY294002 and Akti-1/2. uPAR knockdown significantly increased sensitivity to cisplatin whereas its overexpression significantly decreased cisplatin sensitivity. Furthermore, sera and tissues from MM patients showed significantly high uPAR levels, which suggested the pathogenic role of uPAR in the tumor biology of human MM. In conclusion, our findings indicate that uPAR levels are associated with malignant characteristics and cisplatin sensitivity of MM. In addition to the potential use of uPAR as a prognostic marker, the combination of uPAR abrogation and cisplatin may reveal a promising therapeutic approach for MM.

HER2 induces cell proliferation and invasion of non-small-cell lung cancer by upregulating COX-2 expression via MEK/ERK signaling pathway

HER2 positivity has been well studied in various cancers, but its importance in non-small-cell lung cancer (NSCLC) is still being explored. In this study, quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to detect HER2 and COX-2 expression in NSCLC tissues. Then, pcDNA3.1-HER2 was used to overexpress HER2, while HER2 siRNA and COX-2 siRNA were used to silence HER2 and COX-2 expression. MTT assay and invasion assay were used to detect the effects of HER2 on cell proliferation and invasion. Our study revealed that HER2 and COX-2 expression were upregulated in NSCLC tissues and HER2 exhibited a significant positive correlation with the levels of COX-2 expression. Overexpression of HER2 evidently elevated COX-2 expression, while silencing of HER2 evidently decreased COX-2 expression. Furthermore, overexpressed HER2 induced the ERK phosphorylation, and this was abolished by the treatment with U0126, a pharmacological inhibitor of MEK, an upstream kinase of ERK. HER2-induced expression and promoter activity of COX-2 were also suppressed by U0126, suggesting that the MEK/ERK signaling pathway regulates COX-2 expression. In addition, HER2 induced activation of AKT signaling pathway, which was reversed by pretreatment with U0126 and COX-2 siRNA. MTT and invasion assays revealed that HER2 induced cell proliferation and invasion that were reversed by pretreatment with U0126 and COX-2 siRNA. In this study, our results demonstrated for the first time that HER2 elevated COX-2 expression through the activation of MEK/ERK pathway, which subsequently induced cell proliferation and invasion via AKT pathway in NSCLC tissues.

Apoptosis prediction via inhibition of AKT signaling pathway by neogrifolin

Neogrifolin, a natural biologically active substance isolated from the edible bodies of the mushroom Albatrellus confluens, has been shown to possess several pharmacological properties. No studies were investigated against osteosarcoma cancer. Hence, in this study, we investigated the apoptosis-inducing effects and the mechanisms of neogrifolin on human osteosarcoma cells. Our results demonstrated that neogrifolin induced concentration- and time-dependent suppression of proliferation. Further, induction of apoptosis in U2OS and MG63 osteosarcoma cell lines were also observed. Neogrifolin induced the release of cytochrome c accompanied by activation of caspase-9, caspase-3 and cleavage of poly (ADP-ribose) polymerase (PARP). In addition, z-VAD-fmk, a universal inhibitor of caspases, prevented caspase-3 activation and PARP cleavage and inhibited neogrifolin-induced cell growth inhibition. Furthermore, neogrifolin treatment resulted in a reduction of phosphorylated AKT level, FOXO transcription factor, and glycogen synthase kinase 3 (GSK3). Knockdown of GSK3 with siRNA inhibited the apoptotic effects of neogrifolin. On the other hand, neogrifolin treatment also down-regulated the expression of the inhibitor of apoptosis protein (IAP) in both osteosarcoma cells. Collectively, our results suggested that neogrifolin is a potential candidate for osteosarcoma.

Review: putative roles for the macrophage migratory inhibitory factor at the maternal fetal interface

Complex and dynamic networks of molecules participate in the essential interactions between maternal organism, placenta and fetus in a healthy and successful pregnancy. Macrophage migratory inhibitory factor (MIF) is one of several molecules produced at implantation sites; MIF is mostly expressed by trophoblast cells. This has led to expectations of MIF's relevance as a partner in the maternal/fetal dialog. MIF is known by its biological interactions and functional roles as an activator of innate immunity, regulating subsequent adaptive responses, which include inhibition of migration of mononuclear cells in vitro, antagonism of glucocorticoids, and regulation of expression of Toll-like receptor 4. Beyond roles in the inflammatory response, MIF can interfere with proliferative activities in different cell types, as well as with cell death pathways. This intriguing factor found at the human, porcine, ovine, bovine and rodent maternal-fetal interfaces is present in a time- and spatially-dependent manner, indicating regulatory roles in the process of embryo implantation, placental development, maintenance of pregnancy and birth. Here, we will review MIF participation in placental physiology, including new evidence for a dialog with uterine cells, and a potential role in protection of uterine decidual cells.