Low-dose interleukin-2 alleviates dextran sodium sulfate-induced colitis in mice by recovering intestinal integrity and inhibiting AKT-dependent pathways

Several phase 1/2 clinical trials showed that low-dose interleukin-2 (IL-2) treatment is a safe and effective strategy for the treatment of chronic graft-versus-host disease, hepatitis C virus-induced vasculitis, and type 1 diabetes. Ulcerative colitis (UC) is a chronic inflammatory condition of the colon that lacks satisfactory treatment. In this study, we aimed to determine the effects of low-dose IL-2 as a therapeutic for UC on dextran sulfate sodium (DSS)-induced colitis. Methods: Mice with DSS-induced colitis were intraperitoneally injected with low-dose IL-2. Survival, body weight, disease activity index, colon length, histopathological score, myeloperoxidase activity and inflammatory cytokine levels as well as intestinal barrier integrity were examined. Differential gene expression after low-dose IL-2 treatment was analyzed by RNA-sequencing. Results: Low-dose IL-2 significantly improved the symptoms of DSS-induced colitis in mice and attenuated pro-inflammatory cytokine production and immune cell infiltration. The most effective dose range of IL-2 was 16K-32K IU/day. Importantly, low-dose IL-2 was effective in ameliorating the disruption of epithelial barrier integrity in DSS-induced colitis tissues by restoring tight junction proteins and mucin production and suppressing apoptosis. The colon tissue of DSS-induced mice exposed to low-dose IL-2 mimic gene expression patterns in the colons of control mice. Furthermore, we identified the crucial role of the PI3K-AKT pathway in exerting the therapeutic effect of low-dose IL-2. Conclusions: The results of our study suggest that low-dose IL-2 has therapeutic effects on DSS-induced colitis and potential clinical value in treating UC.

Triterpenoids from Liquidambar Fructus induced cell apoptosis via a PI3K-AKT related signal pathway in SMMC7721 cancer cells

A previously undescribed taraxerene-type triterpenoid possessing a class of rare natural taraxerene triterpenoid possessing skeleton with 14, 28-lactone, two undescribed oleane-type triterpenoids, and twenty-five known triterpenoids were isolated from Liquidambar formosana (Hamamelidaceae). The structures of undescribed compounds were determined on the basis of 1D and 2D NMR spectroscopic, HR-ESI-MS, and X-ray crystallographic data analysis. Among the isolates, ursolic acid, 3,6-dion-20(29)-lupen-28-oic acid, and 3-oxo-12α-hydroxyoleanan-28,13β-olide induced a significant apoptosis in SMMC7721 cells in the flow cytometer experiment with apoptosis rates of 94.5%, 57.3% and 89.9% at 8.0 μM, respectively, exhibiting near equivalent apoptosis-inducing abilities to that positive drug taxol (apoptotic rate of 71.2% at 1.4 μM). Mechanism studies suggested that these three compounds could regulate the mitochondrial pathway by up-regulating the expressions of pro-apoptotic factors (Bad and Bax) and activating caspase-3 and caspase-9 to induce apoptosis. Further studies indicated that the pro-apoptotic effects of these three compounds were associated with PI3K-AKT pathway inhibition. Taken together, these studies provide evidence that triterpenoids from L. Fructus are promising candidates for the hepatocellular carcinoma therapy.

Tumour angiogenesis and c-Met pathway activation - implications in breast cancer

Breast cancer is a heterogeneous disease with wide range of clinical behaviour. Tumour angiogenesis and metastasis have been considered as prognostic markers of the breast carcinoma, and c-Met, a transmembrane receptor tyrosine kinase has been implicated in both these processes of tumour progression. This study was conducted to elucidate c-Met and downstream signalling pathways in breast cancer and correlate with angiogenesis as assessed by microvessel density (MVD) and other prognostic parameters including lymph node metastases. Microvessel density (MVD) was assessed by endothelial cell (CD34) marker in breast cancers. c-Met was evaluated by immunohistochemistry for protein expression and by copy number assay for amplification at gene level. PCR array for gene expression related to c-Met, RAS-MAPK, PI3K-AKT and angiogenesis pathway was performed by real-time PCR. c-Met protein, copy number and mRNA expression did not differ significantly with the lymph node status or MVD. However, Her-2 overexpressing group showed c-Met protein overexpression and amplification. c-Met protein overexpression was also noted in the Luminal B subtype though no amplification was noted. Thus, the c-Met immunohistochemistry score and the c-MET copy numbers did not correlate with each other. c-Met downstream pathway genes (RAS-MAPK, PI3K-AKT and angiogenesis pathway) showed significant upregulation in Luminal B molecular subtype, lymph node-positive cases and cases with high MVD. The downstream signalling pathways (angiogenesis, RAS-MAPK and PI3K-AKT) were associated high MVD, lymph node metastases, and Her-2 and Luminal B subtype. Since inhibitors of these pathways are commercially available, these can be of therapeutic significance.

Modulation of mitochondrial respiration underpins neuronal differentiation enhanced by lutein

Lutein is a dietary carotenoid of particular nutritional interest as it is preferentially taken up by neural tissues. Often linked with beneficial effects on vision, a broader role for lutein in neuronal differentiation has emerged recently, although the underlying mechanisms for these effects are not yet clear. The purpose of this study was to investigate the effect of lutein on neuronal differentiation and explore the associated underpinning mechanisms. We found that lutein treatment enhanced the differentiation of SH-SY5Y cells, specifically increasing neuronal arborization and expression of the neuronal process filament protein microtubule-associated protein 2. This effect was mediated by the intracellular phosphoinositide-3-kinase (PI3K) signaling pathway. While PI3K activity is a known trigger of neuronal differentiation, more recently it has also been shown to modulate the metabolic state of cells. Our analysis of bioenergetics found that lutein treatment increased glucose consumption, rates of glycolysis and enhanced respiratory activity of mitochondrial complexes. Concomitantly, the generation of reactive oxygen species was increased (consistent with previous reports that reactive oxygen species promote neuronal differentiation), as well as the production of the key metabolic intermediate acetyl-CoA, an essential determinant of epigenetic status in the cell. We suggest that lutein-stimulated neuronal differentiation is mediated by PI3K-dependent modulation of mitochondrial respiration and signaling, and that the consequential metabolic shifts initiate epigenetically dependent transcriptomic reprogramming in support of this morphogenesis. These observations support the potential importance of micronutrients supplementation to neurogenesis, both during normal development and in regenerative repair.

microRNA-186 inhibition of PI3K-AKT pathway via SPP1 inhibits chondrocyte apoptosis in mice with osteoarthritis

Chondrocyte apoptosis has been implicated as a major pathological osteoarthritis (OA) change in humans and experimental animals. We evaluate the ability of miR-186 on chondrocyte apoptosis and proliferation in OA and elucidate the underlying mechanism concerning the regulation of miR-186 in OA. Gene expression microarray analysis was performed to screen differentially expressed messenger RNAs (mRNAs) in OA. To validate the effect of miR-186 on chondrocyte apoptosis, we upregulated or downregulated endogenous miR-186 using mimics or inhibitors. Next, to better understand the regulatory mechanism for miR-186 governing SPP1, we suppressed the endogenous expression of SPP1 by small interfering RNA (siRNA) against SPP1 in chondrocytes. We identified SPP1 is highly expressed in OA according to an mRNA microarray data set GSE82107. After intra-articular injection of papain into mice, the miR-186 is downregulated while the SPP1 is reciprocal, with dysregulated PI3K-AKT pathway in OA cartilages. Intriguingly, miR-186 was shown to increase chondrocyte survival, facilitate cell cycle entry in OA chondrocytes, and inhibit chondrocyte apoptosis in vitro by modulation of pro- and antiapoptotic factors. The determination of luciferase activity suggested that miR-186 negatively targets SPP1. Furthermore, we found that the effect of miR-186 suppression on OA chondrocytes was lost when SPP1 was suppressed by siRNA, suggesting that miR-186 affected chondrocytes by targeting and depleting SPP1, a regulator of PI3K-AKT pathway. Our findings reveal a novel mechanism by which miR-186 inhibits chondrocyte apoptosis in OA by interacting with SPP1 and regulating PI3K-AKT pathway. Restoring miR-186 might be a future therapeutic strategy for OA.

Galangin Induces p53-independent S-phase Arrest and Apoptosis in Human Nasopharyngeal Carcinoma Cells Through Inhibiting PI3K-AKT Signaling Pathway

BACKGROUND/AIM

Anti-cancer activity of 3,5,7-trihydroxyflavone (galangin) has been documented in a variety of cancer types; however, its effect on human nasopharyngeal carcinoma (NPC) cells remains undetermined.

MATERIALS AND METHODS

Human NPC cell lines were treated with galangin. Apoptosis was analyzed by assessing nuclear condensation, cleavage of pro-caspase-3 and poly ADP-ribose polymerase (PARP), and DNA fragmentation. Short hairpin RNA-mediated silencing of p53 was used for characterizing the role of p53 in the anti-cancer activity of galangin. Phosphatidylinositol 3-kinase (PI3K) inhibitor, protein kinase B (AKT) inhibitor, and ectopic expression of wild type p85α or p85α mutant lacking p110α-binding ability were utilized to confirm the involvement of PI3K/AKT inactivation in galangin-induced apoptosis.

RESULTS

Galangin induces apoptosis and S-phase arrest by attenuating the PI3K/AKT signaling pathway. Silencing of p53 did not block the anti-cancer activity of galangin on NPC cells.

CONCLUSION

Galangin effects on apoptosis and S-phase arrest in NPC cells are mediated via interfering with the PI3K-AKT signaling pathway in a p53-independent manner.

Caffeine-mediated BDNF release regulates long-term synaptic plasticity through activation of IRS2 signaling

Caffeine has cognitive‐enhancing properties with effects on learning and memory, concentration, arousal and mood. These effects imply changes at circuital and synaptic level, but the mechanism by which caffeine modifies synaptic plasticity remains elusive. Here we report that caffeine, at concentrations representing moderate to high levels of consumption in humans, induces an NMDA receptor‐independent form of LTP (_CAFLTP) in the CA1 region of the hippocampus by promoting calcium‐dependent secretion of BDNF, which subsequently activates TrkB‐mediated signaling required for the expression of _CAFLTP. Our data include the novel observation that insulin receptor substrate 2 (IRS2) is phosphorylated during induction of _CAFLTP, a process that requires cytosolic free Ca²⁺. Consistent with the involvement of IRS2 signals in caffeine‐mediated synaptic plasticity, phosphorylation of Akt (Ser473) in response to LTP induction is defective in Irs2^−/− mice, demonstrating that these plasticity changes are associated with downstream targets of the phosphoinositide 3‐kinase (PI3K) pathway. These findings indicate that TrkB‐IRS2 signals are essential for activation of PI3K during the induction of LTP by caffeine.

Targeting the Akt/PI3K Signaling Pathway as a Potential Therapeutic Strategy for the Treatment of Pancreatic Cancer

The phosphoinositide 3 kinase AKT mammalian target of rapamycin (PI3K-AKTmTOR) signaling pathway is an important in the aetiology of pancreatic cancer (PC) and is frequently activated in PC. It is then associated with a poorer prognosis. Aberrant activation of this pathway is involved in cell metabolism and survival, cell cycle progression, regulation of apoptosis, protein synthesis, and genomic instability. Several agents have been developed to target the Akt/PI3K pathways, including PI3K inhibitors, (e.g. LY294002, Wortmannin), PI3K/mTOR inhibitors (e.g. BEZ235), or Akt inhibitors (e.g. perifosine, MK2206), which have been tested alone or in combinations with DNA-targeted agents (e.g., gemcitabine and fluorouracil) in pancreatic ductal adenocarcinoma (PDAC). However, due to their unfavorable pharmaceutical activities, toxicity, and crossover inhibition of other lipid and protein kinases, these compounds have not been used in clinical studies. In this review, we focus on the progress in the development of Akt, PI3K and mTOR inhibitors for clinical applications, together with the need for the development of in PDAC and the need for the identification of predictive biomarkers and combination strategies with less toxicity in counteracting the mechanisms of resistance to the therapy.

SIX4 promotes metastasis via activation of the PI3K-AKT pathway in colorectal cancer

Background

Several studies report aberrant expression of sine oculis homeobox (SIX) homolog family members during cancer development and progression. SIX4 participates in organ development, such as myogenesis and neurogenesis. However, the expression and clinical implication of SIX4 in colorectal cancer (CRC) remains unclear.

Methods

The SIX4 expression levels in colorectal patients were assessed in nine different human cancer arrays and compared using patient survival data. SIX4 expression was silenced in two cell culture lines for invasion and wound healing assessment. Finally, bioinformatics assessments ascertained the pathways impacted by SIX4.

Results

SIX4 was upregulated in The Cancer Genome Atlas CRC cohort and other gene expression omnibus (GEO) cohorts. In addition, SIX4 expression significantly correlated with lymph node metastasis and advanced Tumor Node Metastasis (TNM) stages. Moreover, SIX4 overexpression was related to unfavorable prognosis in CRC patients. Silencing SIX4 inhibited CRC cell metastasis by surpressing AKT phosphorylation.

Discussion

SIX4 is upregulated in CRC and can be used as a prognosis biomarker.

Etiopathogenesis of Differentiated Thyroid Carcinomas

INTRODUCTION

Thyroid malignomas are a heterogeneous group of neoplasm consisting of most frequent differentiated encountered carcinomas, papillary and follicular thyroid carcinoma, then medullary thyroid carcinoma originating from neuroendocrine calcitonin-producing C-cells and rare forms of thyroid lymphomas arising from intrathyroidal lymphatic tissue, thyroid sarcomas and poorly differentiated anaplastic thyroid carcinoma. There are increasing numbers of epidemiological studies and publications that have suggested increased incidence rate of thyroid carcinomas. We have read, analysed and compare available reviews and original articles investigating different etiological factors in the development of thyroid carcinomas through Google Scholar and PubMed Database.

DISCUSSION

Aetiology involved in the development of thyroid carcinomas is multifactorial and includes external influences, as well as constitutional predispositions and genetic etiological factors. The actual effect of environmental and constitutional factors is on promoting genetic and epigenetic alterations which result in cell proliferation and oncogenesis. Until now are identified numerous genetic alterations, assumed to have an important role in oncogenesis, with MAPK and PI3K-AKT as crucial signalling networks regulating growth, proliferation, differentiation and cell survival/apoptosis.

CONCLUSION

This new molecular insight could have a crucial impact on diagnosis and also on improving and selecting an appropriate treatment to the patients with thyroid malignancies.

SPIB is a novel prognostic factor in diffuse large B-cell lymphoma that mediates apoptosis via the PI3K-AKT pathway

Although the clinical outcomes of diffuse large B-cell lymphoma (DLBCL) have improved in the immunochemotherapy era, approximately one-third of patients develop intractable disease. To improve clinical outcomes for these patients, it is important to identify those with poor prognosis prior to initial treatment in order to select optimal therapies. Here, we investigated the clinical and biological significance of SPIB, an Ets family transcription factor linked to lymphomagenesis, in DLBCL. We classified 134 DLBCL patients into SPIB negative (n = 108) or SPIB positive (n = 26) groups by immunohistochemical staining. SPIB positive patients had a significantly worse treatment response and poor prognosis compared with SPIB negative patients. Multivariate analysis for patient survival indicated that SPIB expression was an independent poor prognostic factor for both progression free survival (PFS) and overall survival (OS) (PFS, hazard ratio [HR] 2.65, 95% confidence interval [CI] 1.31-5.33, P = 0.006; OS, HR 3.56, 95% CI 1.43-8.91, P = 0.007). Subsequent analyses of the roles of SPIB expression in DLBCL pathogenesis revealed that SPIB expression in lymphoma cells resulted in resistance to the BH3-mimetic ABT-263 and contributed to apoptosis resistance via the PI3K-AKT pathway. The inhibition of AKT phosphorylation re-sensitized SPIB expressing lymphoma cells to ABT-263-induced cell death. Together, our data indicate that SPIB expression is a clinically novel poor prognostic factor in DLBCL that contributes to treatment resistance, at least in part, through an anti-apoptotic mechanism.

Antitumor effect of manumycin on colorectal cancer cells by increasing the reactive oxygen species production and blocking PI3K-AKT pathway

Manumycin is a natural, well-tolerated microbial metabolite and is regarded as a farnesyltransferase inhibitor. Some data suggest that manumycin inhibits proliferation of diverse cancer cells through various pathways. However, the antitumor effect of manumycin on colorectal cancer (CRC) remains unknown. In the present study, we investigated the antitumor effect of manumycin on CRC in vitro and in vivo. The results of cell viability assay revealed that the proliferation of the CRC cells was significantly inhibited by manumycin. Moreover, cell apoptosis induced by manumycin was also found in a time- and dose-dependent manner. Interestingly, treatment of the CRC cells with manumycin resulted in increased generation of reactive oxygen species. Subsequently, manumycin also decreased the phosphorylation of phosphatidylinositol 3-kinase (PI3K) and AKT, as well as the expression of caspase-9 and poly(ADP-ribose) polymerase (PARP) in a time-dependent manner. In addition, we found that N-acetyl-l-cysteine (NAC) attenuated the effect of manumycin on the PI3K-AKT pathway, and wortmannin reduced the effect of manumycin on caspase-9 and PARP expression. More importantly, the anticancer effect of manumycin was also observed in established tumor xenografts. Taken together, these findings supported the potential application of manumycin against colorectal carcinoma.

Survivin Down-regulation by α-Santalol Is Not Mediated Through PI3K-AKT Pathway in Human Breast Cancer Cells

BACKGROUND

α-Santalol, a terpenoid found in sandalwood oil, has been shown to inhibit cancer cell growth in vitro by inducing apoptosis. This study was performed to investigate the anticancer properties of α-santalol associated with the induction of apoptosis in cultured MCF-7 [estrogen receptor (ER)-positive, and wild-type p53)] and MDA-MB-231 (ER-negative and mutant p53) breast cancer cells.

MATERIALS AND METHODS

Expression of major proteins examined in the study were determined using a standard western blot protocol and analyzed by LICOR-Odyssey infra-red scanner. Total protein levels of survivin were confirmed by survivin enzyme-linked immunosorbent assay (ELISA) kit. Cell viability was assessed by the trypan blue dye exclusion assay, and caspase-3 activity was determined by caspase-3 (active) ELISA kit.

RESULTS

Treatment of breast cancer cells for 6 and 9 h with α-santalol (20, and 40 μM) resulted in statistically significant concentration-dependent down-regulation of survivin. Phosphorylated protein kinase B (pAKT) levels were found to be slightly up-regulated despite the down-regulation of survivin. Pharmacological inhibition of the phosphoinositide 3-kinase - protein kinase B (PI3K-AKT) pathway did not result in a synergistic/additive increase in cell death or caspase-3 activity caused by α-santalol.

CONCLUSION

The study reveals that survivin down-regulation by α-santalol in breast cancer cells is not mediated through the PI3K-AKT pathway.