Filamin A Expression Negatively Regulates Sphingosine-1-Phosphate-Induced NF-κB Activation in Melanoma Cells by Inhibition of Akt Signaling

FLNA overexpression promotes papillary thyroid cancer aggression via the FAK/AKT signaling pathway

Background

Filamin A (FLNA) is a member of the filamin family and has been found to be critical for the progression of several cancers. However, its biological function in papillary thyroid cancer (PTC) remains largely unexplored.

Methods

Data from The Cancer Genome Atlas (TCGA) databases were utilized to analyze the FLNA expression level and its influence on the clinical implications of patients with PTC. Gene Expression Omnibus (GEO) and qRT-PCR was used to verify the expression levels of FLNA in PTC. Kaplan-Meier survival analysis was conducted to evaluate the prognostic value of FLNA in PTC. Transwell assays and wound healing were performed to examine the biological function of FLNA knockdown in PTC cells. Gene set enrichment analysis (GSEA) and Western blotting were conducted to investigate the potential mechanisms underlying the role of FLNA in PTC progression. In addition, the relationship between FLNA expression and the tumor immune microenvironment (TME) in PTC was explored.

Results

FLNA was significantly upregulated in PTC tissues. High expression levels of FLNA was correlated with advanced TNM stage, T stage, and N stage, as well as poor disease-free interval (DFI) and progression-free interval (PFI) time in PTC patients. Moreover, we found that FLNA knockdown inhibited the migration and invasion of PTC cells. Mechanistically, FLNA knockdown inhibited epithelial-mesenchymal transition (EMT) in PTC and affected the activation of the FAK/AKT signaling pathway. In addition, FLNA expression was associated with TME in PTC.

Conclusion

FLNA may be regarded as a new therapeutic target for PTC patients.

Filamin A in triple negative breast cancer

Triple-negative breast cancer is a rare but highly heterogeneous breast cancer subtype with a limited choice of specific treatments. Chemotherapy remains the only efficient treatment, but its side effects and the development of resistance consolidate the urgent need to discover new targets. In TNBC, filamin A expression correlates to grade and TNM stage. Accordingly, this protein could constitute a new target for this BC subtype. Even if most of the data indicates its direct involvement in cancer progression, some contrasting results underline the need to deepen the studies. To elucidate a possible function of this protein as a TNBC marker, we summarized the main characteristic of filamin A and its involvement in physiological and pathological processes such as cancer. Lastly, we scrutinized its actions in triple-negative breast cancer and highlighted the need to increase the number of studies useful to better clarify the role of this versatile protein as a marker and target in TNBC, alone or in "collaboration" with other proteins with a relevant role in this BC subgroup.

Sphingosine 1-phosphate elicits a ROS-mediated proinflammatory response in human endometrial stromal cells via ERK5 activation

Endometriosis is a chronic gynecological disease affecting ~10% women in the reproductive age characterized by the growth of endometrial glands and stroma outside the uterine cavity. The inflammatory process has a key role in the initiation and progression of the disorder. Currently, there are no available early diagnostic tests and therapy relies exclusively on symptomatic drugs, so that elucidation of the complex molecular mechanisms involved in the pathogenesis of endometriosis is an unmet need. The signaling of the bioactive sphingolipid sphingosine 1-phosphate (S1P) is deeply dysregulated in endometriosis. S1P modulates a variety of fundamental cellular processes, including inflammation, neo-angiogenesis, and immune responses acting mainly as ligand of a family of G-protein-coupled receptors named S1P receptors (S1PR), S1P1-5 . Here, we demonstrated that the mitogen-activated protein kinase ERK5, that is expressed in endometriotic lesions as determined by quantitative PCR, is activated by S1P in human endometrial stromal cells. S1P-induced ERK5 activation was shown to be triggered by S1P1/3 receptors via a SFK/MEK5-dependent axis. S1P-induced ERK5 activation was, in turn, responsible for the increase of reactive oxygen species and proinflammatory cytokine expression in human endometrial stromal cells. The present findings indicate that the S1P signaling, via ERK5 activation, supports a proinflammatory response in the endometrium and establish the rationale for the exploitation of innovative therapeutic targets for endometriosis.

Melanoma cells with acquired resistance to vemurafenib have decreased autophagic flux and display enhanced ability to transfer resistance

Over the last years, the incidence of melanoma, the deadliest form of skin cancer, has risen significantly. Nearly half of the melanoma patients exhibit the BRAF^V600E mutation. Although the use of BRAF and MEK inhibitors (BRAFi and MEKi) showed an impressive success rate in melanoma patients, durability of response remains an issue because tumor quickly becomes resistant. Here, we generated and characterized Lu1205 and A375 melanoma cells resistant to vemurafenib (BRAFi). Resistant cells (Lu1205R and A375R) exhibit higher IC₅₀ (5-6 fold increase) and phospho-ERK levels and 2-3 times reduced apoptosis than their sensitive parents (Lu1205S and A375S). Moreover, resistant cells are 2-3 times bigger, display a more elongated morphology and have a modulation the migration capacity. Interestingly, pharmacological inhibition of sphingosine kinases, that prevents sphingosine-1-phosphate production, reduces migration of Lu1205R cells by 50 %. In addition, although Lu1205R cells showed increased basal levels of the autophagy markers LC3II and p62, they have decreased autophagosome degradation and autophagy flux. Remarkably, expression of Rab27A and Rab27B, which are involved in the release of extracellular vesicles are dramatically augmented in resistant cells (i.e. 5-7 fold increase). Indeed, conditioned media obtained from Lu1205R cells increased the resistance to vemurafenib of sensitive cells. Hence, these results support that resistance to vemurafenib modulates migration and the autophagic flux and may be transferred to nearby sensitive melanoma cells by factors that are released to the extracellular milieu by resistant cells.

ROR2 promotes epithelial-mesenchymal transition by hyperactivating ERK in melanoma

Receptor tyrosine kinase-like orphan receptor 2 (ROR2) is a protein with important functions during embryogenesis that is dysregulated in human cancer. An intriguing feature of this receptor is that it plays opposite roles in different tumor types either promoting or inhibiting tumor progression. Understanding the complex role of this receptor requires a more profound exploration of both the altered biological and molecular mechanisms. Here, we describe that ROR2 promotes Epithelial-Mesenchymal Transition (EMT) by inducing cadherin switch and the upregulation of the transcription factors ZEB1, Twist, Slug, Snail, and HIF1A, together with a mesenchymal phenotype and increased migration. We show that ROR2 activates both p38 and ERK mitogen-activated protein kinase pathways independently of Wnt5a. Further, we demonstrated that the upregulation of EMT-related proteins depends on the hyperactivation of the ERK pathway far above the typical high constitutive activity observed in melanoma. In addition, ROR2 also promoted ERK phosphorylation, EMT, invasion, and necrosis in xenotransplanted mice. ROR2 also associates with EMT in tumor samples from melanoma patients where analysis of large cohorts revealed that increased ROR2 levels are linked to EMT signatures. This important role of ROR2 translates into melanoma patient' s prognosis since elevated ROR2 levels reduced overall survival and distant metastasis-free survival of patients with lymph node metastasis. In sum, these results demonstrate that ROR2 contributes to melanoma progression by inducing EMT and necrosis and can be an attractive therapeutic target for melanoma.

Sphingosine-1-Phosphate Recruits Macrophages and Microglia and Induces a Pro-Tumorigenic Phenotype That Favors Glioma Progression

Glioblastoma is the most aggressive brain tumor in adults. Treatment failure is predominantly caused by its high invasiveness and its ability to induce a supportive microenvironment. As part of this, a major role for tumor-associated macrophages/microglia (TAMs) in glioblastoma development was recognized. Phospholipids are important players in various fundamental biological processes, including tumor-stroma crosstalk, and the bioactive lipid sphingosine-1-phosphate (S1P) has been linked to glioblastoma cell proliferation, invasion, and survival. Despite the urgent need for better therapeutic approaches, novel strategies targeting sphingolipids in glioblastoma are still poorly explored. Here, we showed that higher amounts of S1P secreted by glioma cells are responsible for an active recruitment of TAMs, mediated by S1P receptor (S1PR) signaling through the modulation of Rac1/RhoA. This resulted in increased infiltration of TAMs in the tumor, which, in turn, triggered their pro-tumorigenic phenotype through the inhibition of NFkB-mediated inflammation. Gene set enrichment analyses showed that such an anti-inflammatory microenvironment correlated with shorter survival of glioblastoma patients. Inhibition of S1P restored a pro-inflammatory phenotype in TAMs and resulted in increased survival of tumor-bearing mice. Taken together, our results establish a crucial role for S1P in fine-tuning the crosstalk between glioma and infiltrating TAMs, thus pointing to the S1P-S1PR axis as an attractive target for glioma treatment.

Sphingosine 1-phosphate signaling in perivascular cells enhances inflammation and fibrosis in the kidney

Chronic kidney disease (CKD), characterized by sustained inflammation and progressive fibrosis, is highly prevalent and can eventually progress to end-stage kidney disease. However, current treatments to slow CKD progression are limited. Sphingosine 1-phosphate (S1P), a product of sphingolipid catabolism, is a pleiotropic mediator involved in many cellular functions, and drugs targeting S1P signaling have previously been studied particularly for autoimmune diseases. The primary mechanism of most of these drugs is functional antagonism of S1P receptor-1 (S1P1) expressed on lymphocytes and the resultant immunosuppressive effect. Here, we documented the role of local S1P signaling in perivascular cells in the progression of kidney fibrosis using primary kidney perivascular cells and several conditional mouse models. S1P was predominantly produced by sphingosine kinase 2 in kidney perivascular cells and exported via spinster homolog 2 (Spns2). It bound to S1P1 expressed in perivascular cells to enhance production of proinflammatory cytokines/chemokines upon injury, leading to immune cell infiltration and subsequent fibrosis. A small-molecule Spns2 inhibitor blocked S1P transport, resulting in suppression of inflammatory signaling in human and mouse kidney perivascular cells in vitro and amelioration of kidney fibrosis in mice. Our study provides insight into the regulation of inflammation and fibrosis by S1P and demonstrates the potential of Spns2 inhibition as a treatment for CKD and potentially other inflammatory and fibrotic diseases that avoids the adverse events associated with systemic modulation of S1P receptors.

ROR2 has a protective role in melanoma by inhibiting Akt activity, cell-cycle progression, and proliferation

BACKGROUND

Receptor tyrosine kinase-like orphan receptor 2 (ROR2) is a Wnt5a receptor aberrantly expressed in cancer that was shown to either suppress or promote carcinogenesis in different tumor types. Our goal was to study the role of ROR2 in melanoma.

METHODS

Gain and loss-of-function strategies were applied to study the biological function of ROR2 in melanoma. Proliferation assays, flow cytometry, and western blotting were used to evaluate cell proliferation and changes in expression levels of cell-cycle and proliferation markers. The role of ROR2 in tumor growth was assessed in xenotransplantation experiments followed by immunohistochemistry analysis of the tumors. The role of ROR2 in melanoma patients was assessed by analysis of clinical data from the Leeds Melanoma Cohort.

RESULTS

Unlike previous findings describing ROR2 as an oncogene in melanoma, we describe that ROR2 prevents tumor growth by inhibiting cell-cycle progression and the proliferation of melanoma cells. The effect of ROR2 is mediated by inhibition of Akt phosphorylation and activity which, in turn, regulates the expression, phosphorylation, and localization of major cell-cycle regulators including cyclins (A, B, D, and E), CDK1, CDK4, RB, p21, and p27. Xenotransplantation experiments demonstrated that ROR2 also reduces proliferation in vivo, resulting in inhibition of tumor growth. In agreement with these findings, a higher ROR2 level favors thin and non-ulcerated primary melanomas with reduced mitotic rate and better prognosis.

CONCLUSION

We conclude that the expression of ROR2 slows down the growth of primary tumors and contributes to prolonging melanoma survival. Our results demonstrate that ROR2 has a far more complex role than originally described.

BCL2L10 Is Overexpressed in Melanoma Downstream of STAT3 and Promotes Cisplatin and ABT-737 Resistance

Simple Summary

BCL2L10 is the sixth and less studied protein from the group of Bcl-2 anti-apoptotic proteins. These proteins are important therapeutic targets since they convey resistance to anticancer regimens. We describe here for the first time the role of BCL2L10 in melanoma. We found that BCL2L10 is abundantly and frequently expressed both in melanoma cell lines and tumor samples. This increased expression is due to the activity of the transcription factor STAT3 that positively regulate BCL2L10 transcription. We describe that Bcl2l10 is a pro-survival factor in melanoma, being able to protect cells from the cytotoxic effect of different drugs, including cisplatin, dacarbazine, and ABT-737. BCL2L10 also inhibited the cell death upon combination treatments of PLX-4032, a BRAF inhibitor, with ABT-737 or cisplatin. In summary, we determined that BCL2L10 is expressed in melanoma and contributes to cell survival. Hence, targeting BCL2L10 may enhance the clinical efficacy of other therapies for malignant melanoma.

Abstract

The anti-apoptotic proteins from the Bcl-2 family are important therapeutic targets since they convey resistance to anticancer regimens. Despite the suspected functional redundancy among the six proteins of this subfamily, both basic studies and therapeutic approaches have focused mainly on BCL2, Bcl-xL, and MCL1. The role of BCL2L10, another member of this group, has been poorly studied in cancer and never has been in melanoma. We describe here that BCL2L10 is abundantly and frequently expressed both in melanoma cell lines and tumor samples. We established that BCL2L10 expression is driven by STAT3-mediated transcription, and by using reporter assays, site-directed mutagenesis, and ChIP analysis, we identified the functional STAT3 responsive elements in the BCL2L10 promoter. BCL2L10 is a pro-survival factor in melanoma since its expression reduced the cytotoxic effects of cisplatin, dacarbazine, and ABT-737 (a BCL2, Bcl-xL, and Bcl-w inhibitor). Meanwhile, both genetic and pharmacological inhibition of BCL2L10 sensitized melanoma cells to cisplatin and ABT-737. Finally, BCL2L10 inhibited the cell death upon combination treatments of PLX-4032, a BRAF inhibitor, with ABT-737 or cisplatin. In summary, we determined that BCL2L10 is expressed in melanoma and contributes to cell survival. Hence, targeting BCL2L10 may enhance the clinical efficacy of other therapies for malignant melanoma.

Influenza A Virus Nucleoprotein Activates the JNK Stress-Signaling Pathway for Viral Replication by Sequestering Host Filamin A Protein

Influenza A virus (IAV) poses a major threat to global public health and is known to employ various strategies to usurp the host machinery for survival. Due to its fast-evolving nature, IAVs tend to escape the effect of available drugs and vaccines thus, prompting the development of novel antiviral strategies. High-throughput mass spectrometric screen of host-IAV interacting partners revealed host Filamin A (FLNA), an actin-binding protein involved in regulating multiple signaling pathways, as an interaction partner of IAV nucleoprotein (NP). In this study, we found that the IAV NP interrupts host FLNA-TRAF2 interaction by interacting with FLNA thus, resulting in increased levels of free, displaced TRAF2 molecules available for TRAF2-ASK1 mediated JNK pathway activation, a pathway critical to maintaining efficient viral replication. In addition, siRNA-mediated FLNA silencing was found to promote IAV replication (87% increase) while FLNA-overexpression impaired IAV replication (65% decrease). IAV NP was observed to be a crucial viral factor required to attain FLNA mRNA and protein attenuation post-IAV infection for efficient viral replication. Our results reveal FLNA to be a host factor with antiviral potential hitherto unknown to be involved in the IAV replication cycle thus, opening new possibilities of FLNA-NP interaction as a candidate anti-influenza drug development target.

S1PR1 as a Novel Promising Therapeutic Target in Cancer Therapy

Sphingosine-1-phosphate (S1P) can regulate several physiological and pathological processes. S1P signaling via its cell surface receptor S1PR1 has been shown to enhance tumorigenesis and stimulate growth, expansion, angiogenesis, metastasis, and survival of cancer cells. S1PR1-mediated tumorigenesis is supported and amplified by activation of downstream effectors including STAT3, interleukin-6, and NF-κB networks. S1PR1 signaling can also trigger various other signaling pathways involved in carcinogenesis including activation of PI3K/AKT, MAPK/ERK1/2, Rac, and PKC/Ca, as well as suppression of cyclic adenosine monophosphate (cAMP). It also induces immunological tolerance in the tumor microenvironment, while the immunosuppressive function of S1PR1 can also lead to the generation of pre-metastatic niches. Some tumor cells upregulate S1PR1 signaling pathways, which leads to drug resistant cancer cells, mainly through activation of STAT3. This signaling pathway is also implicated in some inflammatory conditions leading to the instigation of inflammation-driven cancers. Furthermore, it can also increase survival via induction of anti-apoptotic pathways, for instance, in breast cancer cells. Therefore, S1PR1 and its signaling pathways can be considered as potential anti-tumor therapeutic targets, alone or in combination therapies. Given the oncogenic nature of S1PR1 and its distribution in a variety of cancer cell types along with its targeting advantages over other molecules of this family, S1PR1 should be considered a favorable target in therapeutic approaches to cancer. This review describes the role of S1PR1 in cancer development and progression, specifically addressing breast cancer, glioma, and hematopoietic malignancies. We also discuss the potential use of S1P signaling modulators as therapeutic targets in cancer therapy.

Significance of 5-S-Cysteinyldopa as a Marker for Melanoma

Melanoma is one of the most lethal and malignant cancers and its incidence is increasing worldwide, and Japan is not an exception. Although there are numerous therapeutic options for melanoma, the prognosis is still poor once it has metastasized. The main concern after removal of a primary melanoma is whether it has metastasized, and early detection of metastatic melanoma would be effective in improving the prognosis of patients. Thus, it is very important to identify reliable methods to detect metastases as early as possible. Although many prognostic biomarkers (mainly for metastases) of melanoma have been reported, there are very few effective for an early diagnosis. Serum and urinary biomarkers for melanoma diagnosis have especially received great interest because of the relative ease of sample collection and handling. Several serum and urinary biomarkers appear to have significant potential both as prognostic indicators and as targets for future therapeutic methods, but still there are no efficient serum and urinary biomarkers for early detection, accurate diagnosis and prognosis, efficient monitoring of the disease and reliable prediction of survival and recurrence. Levels of 5-S-cysteinyldopa (5SCD) in the serum or urine as biomarkers of melanoma have been found to be significantly elevated earlier and to reflect melanoma progression better than physical examinations, laboratory tests and imaging techniques, such as scintigraphy and echography. With recent developments in the treatment of melanoma, studies reporting combinations of 5SCD levels and new applications for the treatment of melanoma are gradually increasing. This review summarizes the usefulness of 5SCD, the most widely used and well-known melanoma marker in the serum and urine, compares 5SCD and other useful markers, and finally its application to other fields.

S1P Signaling in the Tumor Microenvironment

Sphingosine-1-phosphate (S1P), together with other phosphosphingolipids, has been found to regulate complex cellular function in the tumor microenvironment (TME) where it acts as a signaling molecule that participates in cell-cell communication. S1P, through intracellular and extracellular signaling, was found to promote tumor growth, angiogenesis, chemoresistance, and metastasis; it also regulates anticancer immune response, modulates inflammation, and promotes angiogenesis. Interestingly, cancer cells are capable of releasing S1P and thus modifying the behavior of the TME components in a way that contributes to tumor growth and progression. Therefore, S1P is considered an important therapeutic target, and several anticancer therapies targeting S1P signaling are being developed and tested in clinics.

Sphingosine 1-Phosphate (S1P)/ S1P Receptor Signaling and Mechanotransduction: Implications for Intrinsic Tissue Repair/Regeneration

Tissue damage, irrespective from the underlying etiology, destroys tissue structure and, eventually, function. In attempt to achieve a morpho-functional recover of the damaged tissue, reparative/regenerative processes start in those tissues endowed with regenerative potential, mainly mediated by activated resident stem cells. These cells reside in a specialized niche that includes different components, cells and surrounding extracellular matrix (ECM), which, reciprocally interacting with stem cells, direct their cell behavior. Evidence suggests that ECM stiffness represents an instructive signal for the activation of stem cells sensing it by various mechanosensors, able to transduce mechanical cues into gene/protein expression responses. The actin cytoskeleton network dynamic acts as key mechanotransducer of ECM signal. The identification of signaling pathways influencing stem cell mechanobiology may offer therapeutic perspectives in the regenerative medicine field. Sphingosine 1-phosphate (S1P)/S1P receptor (S1PR) signaling, acting as modulator of ECM, ECM-cytoskeleton linking proteins and cytoskeleton dynamics appears a promising candidate. This review focuses on the current knowledge on the contribution of S1P/S1PR signaling in the control of mechanotransduction in stem/progenitor cells. The potential contribution of S1P/S1PR signaling in the mechanobiology of skeletal muscle stem cells will be argued based on the intriguing findings on S1P/S1PR action in this mechanically dynamic tissue.

Searching new structural scaffolds for BRAF inhibitors. An integrative study using theoretical and experimental techniques

The identification of the V600E activating mutation in the protein kinase BRAF in around 50% of melanoma patients has driven the development of highly potent small inhibitors (BRAFi) of the mutated protein. To date, Dabrafenib and Vemurafenib, two specific BRAFi, have been clinically approved for the treatment of metastatic melanoma. Unfortunately, after the initial response, tumors become resistant and patients develop a progressive and lethal disease, making imperative the development of new therapeutic options. The main objective of this work was to find new BRAF inhibitors with different structural scaffolds than those of the known inhibitors. Our study was carried out in different stages; in the first step we performed a virtual screening that allowed us to identify potential new inhibitors. In the second step, we synthesized and tested the inhibitory activity of the novel compounds founded. Finally, we conducted a molecular modelling study that allowed us to understand interactions at the molecular level that stabilize the formation of the different molecular complexes. Our theoretical and experimental study allowed the identification of four new structural scaffolds, which could be used as starting structures for the design and development of new inhibitors of BRAF. Our experimental data indicate that the most active compounds reduced significantly ERK½ phosphorylation, a measure of BRAF inhibition, and cell viability. Thus, from our theoretical and experimental results, we propose new substituted hydroxynaphthalenecarboxamides, N-(hetero)aryl-piperazinylhydroxyalkylphenylcarbamates, substituted piperazinylethanols and substituted piperazinylpropandiols as initial structures for the development of new inhibitors for BRAF. Moreover, by performing QTAIM analysis, we are able to describe in detail the molecular interactions that stabilize the different Ligand-Receptor complexes. Such analysis indicates which portion of the different molecules must be changed in order to obtain an increase in the binding affinity of these new ligands.

Prion protein is required for tumor necrosis factor α (TNFα)-triggered nuclear factor κB (NF-κB) signaling and cytokine production

The expression of normal cellular prion protein (PrP) is required for the pathogenesis of prion diseases. However, the physiological functions of PrP remain ambiguous. Here, we identified PrP as being critical for tumor necrosis factor (TNF) α-triggered signaling in a human melanoma cell line, M2, and a pancreatic ductal cell adenocarcinoma cell line, BxPC-3. In M2 cells, TNFα up-regulates the expression of p-IκB-kinase α/β (p-IKKα/β), p-p65, and p-JNK, but down-regulates the IκBα protein, all of which are downstream signaling intermediates in the TNF receptor signaling cascade. When PRNP is deleted in M2 cells, the effects of TNFα are no longer detectable. More importantly, p-p65 and p-JNK responses are restored when PRNP is reintroduced into the PRNP null cells. TNFα also activates NF-κB and increases TNFα production in wild-type M2 cells, but not in PrP-null M2 cells. Similar results are obtained in the BxPC-3 cells. Moreover, TNFα activation of NF-κB requires ubiquitination of receptor-interacting serine/threonine kinase 1 (RIP1) and TNF receptor-associated factor 2 (TRAF2). TNFα treatment increases the binding between PrP and the deubiquitinase tumor suppressor cylindromatosis (CYLD), in these treated cells, binding of CYLD to RIP1 and TRAF2 is reduced. We conclude that PrP traps CYLD, preventing it from binding and deubiquitinating RIP1 and TRAF2. Our findings reveal that PrP enhances the responses to TNFα, promoting proinflammatory cytokine production, which may contribute to inflammation and tumorigenesis.

Changes of Foxo3a in PBMCs and its associations with stress hyperglycemia in acute obstructive suppurative cholangitis patients

Objective

The levels of Foxo3a in the peripheral blood mononuclears cells (PBMCs) before and after treatment were detected in acute obstructive suppurative cholangitis (AOSC) patients to evaluate the associations between Foxo3a and stress hyperglycemia (SHG).

Methods

PBMCs were obtained from AOSC patients (n=28) on admission (AP), from patients at 1 week after cure (RP) and from healthy volunteers (HV) (n=14) to evaluate the relationship between the protein levels of Foxo3a and the serum levels of glucose. Signaling pathways, which link inflammation and glycometabolism, simultaneously affecting the expression of Foxo3a, were detected. In addition, cytokines were detected in PBMCs and AOSC mouse models, which were pre-treated with Foxo3a agonist.

Results

The levels of glucose and p-Foxo3a in the AP were significantly higher than those in the RP and HV, where as the levels of Foxo3a in the AP were lower than those in the RP and HV. Foxo3a levels in the AP normalized against RP were strongly negatively correlated with the glucose levels in the AP normalized against RP. The levels of sphingosine-1-phosphate receptor 2 (S1PR2) in the AP were higher than those in the RP and HV. In addition, inhibition of Foxo3a phosphorylation, coupled with the down-regulation of S1PR2, attenuated the LPS-induced inflammatory response in the PBMCs and AOSC mouse models.

Conclusions

Foxo3a is correlated with the dysregulation of glucose homeostasis in the pathogenesis of AOSC-induced sepsis by inhibiting the activation of PI3K/Akt-S1PR2 and NF-κB pathways, hinting at a switched role and therapeutic potentialities in the early stage of sepsis.

Targeting protein kinase-b3 (akt3) signaling in melanoma

INTRODUCTION

Deregulated Akt activity leading to apoptosis inhibition, enhanced proliferation and drug resistance has been shown to be responsible for 35-70% of advanced metastatic melanomas. Of the three isoforms, the majority of melanomas have elevated Akt3 expression and activity. Hence, potent inhibitors targeting Akt are urgently required, which is possible only if (a) the factors responsible for the failure of Akt inhibitors in clinical trials is known; and (b) the information pertaining to synergistically acting targeted therapeutics is available. Areas covered: This review provides a brief introduction of the PI3K-Akt signaling pathway and its role in melanoma development. In addition, the functional role of key Akt pathway members such as PRAS40, GSK3 kinases, WEE1 kinase in melanoma development are discussed together with strategies to modulate these targets. Efficacy and safety of Akt inhibitors is also discussed. Finally, the mechanism(s) through which Akt leads to drug resistance is discussed in this expert opinion review. Expert opinion: Even though Akt play key roles in melanoma tumor progression, cell survival and drug resistance, many gaps still exist that require further understanding of Akt functions, especially in the (a) metastatic spread; (b) circulating melanoma cells survival; and

Melatonin prevents deregulation of the sphingosine kinase/sphingosine 1-phosphate signaling pathway in a mouse model of diethylnitrosamine-induced hepatocellular carcinoma

The sphingosine kinase (SphK)/sphingosine 1-phosphate (S1P) pathway is involved in multiple biological processes, including carcinogenesis. Melatonin shows beneficial effects in cell and animal models of hepatocellular carcinoma, but it is unknown if they are associated with the modulation of the SphK/S1P system, along with different downstream signaling pathways modified in cancer. We investigated the effects of melatonin in mice which received diethylnitrosamine (DEN) (35 mg/kg body weight i.p) once a week for 8 weeks. Melatonin was given at 5 or 10 mg/kg/day i.p. beginning 4 weeks after the onset of DEN administration and ending at the sacrifice time (10, 20, 30, or 40 weeks). Melatonin alleviated the distortion of normal hepatic architecture, lowered the incidence of preneoplastic/neoplastic lesions, and inhibited the expression of proliferative/cell cycle regulatory proteins (Ki67, PCNA, cyclin D1, cyclin E, CDK4, and CDK6). S1P levels and expression of SphK1, SphK2, and S1P receptors (S1PR1/S1PR3) were significantly elevated in DEN-treated mice. However, there was a decreased expression of S1P lyase. These effects were significantly abrogated in a time- and dose-dependent manner by melatonin, which also increased S1PR2 expression. Following DEN treatment, mice exhibited increased phosphorylation of PI3K, AKT, mTOR, STAT3, ERK, and p38, and a higher expression of NF-κB p50 and p65 subunits. Melatonin administration significantly inhibited those changes. Data obtained suggest a contribution of the SphK/S1P system and related signaling pathways to the protective effects of melatonin in hepatocarcinogenesis.

In Vitro Methods to Study the Modulation of Migration and Invasion by Sphingosine-1-Phosphate

Sphingosine-1-phosphate (S1P) is a bioactive lipid that modulates migratory behavior of cells during embryonic development. In addition, S1P might promote tumor progression by enhancing migratory ability and invasiveness of tumor cells. Migration is a complex process that implies cytoskeletal reorganization and formation of structures that enable cell movement. Besides having similar requirements than migration, invasion also involves proteolytic degradation of extracellular matrix (ECM). Matrix metalloproteases (MMPs) have been identified to break down components of the ECM, allowing cancer cells to spread out of the primary tumor. In this chapter, we will describe different techniques to study migration and invasion induced by S1P. To this end, we include detailed protocols of end-point assays to study migration/invasion, and zymography assay to analyze MMP-2 and MMP-9 activity that were standardized in our laboratory in human melanoma cell lines.

Rapid emergence and mechanisms of resistance by U87 glioblastoma cells to doxorubicin in an in vitro tumor microfluidic ecology

In vitro prediction of the probable rapid emergence of resistance to a drug in tumors could act to winnow out potential candidates for further costly development. We have developed a microfluidic device consisting of ∼500 hexagonal microcompartments that provides a complex ecology with wide ranges of drug and nutrient gradients and local populations. This ecology of a fragmented metapopulation induced the drug resistance in stage IV U87 glioblastoma cells to doxorubicin in 7 d. Exome and transcriptome sequencing of the resistant cells identified mutations and differentially expressed genes. Gene ontology and pathway analyses of the genes identified showed that they were functionally relevant to the established mechanisms of doxorubicin action. Specifically, we identified (i) a frame-shift insertion in the filamin-A gene, which regulates the influx and efflux of topoisomerase II poisons; (ii) the overexpression of aldo-keto reductase enzymes, which convert doxorubicin into doxorubicinol; and (iii) activation of NF-κB via alterations in the nucleotide-binding oligomerization domain (NOD)-like receptor signaling pathway from mutations in three genes (CARD6, NSD1, and NLRP13) and the overexpression of inflammatory cytokines. Functional experiments support the in silico analyses and, together, demonstrate the effects of these genetic changes. Our findings suggest that, given the rapid evolution of resistance and the focused response, this technology could act as a rapid screening modality for genetic aberrations leading to resistance to chemotherapy as well as counter selection of drugs unlikely to be successful ultimately.

Sphingosine-1 Phosphate: A New Modulator of Immune Plasticity in the Tumor Microenvironment

In the last 15 years, increasing evidences demonstrate a strong link between sphingosine-1-phosphate (S1P) and both normal physiology and progression of different diseases, including cancer and inflammation. Indeed, numerous studies show that tissue levels of this sphingolipid metabolite are augmented in many cancers, affecting survival, proliferation, angiogenesis, and metastatic spread. Recent insights into the possible role of S1P as a therapeutic target has attracted enormous attention and opened new opportunities in this evolving field. In this review, we will focus on the role of S1P in cancer, with particular emphasis in new developments that highlight the many functions of this sphingolipid in the tumor microenvironment. We will discuss how S1P modulates phenotypic plasticity of macrophages and mast cells, tumor-induced immune evasion, differentiation and survival of immune cells in the tumor milieu, interaction between cancer and stromal cells, and hypoxic response.