Frequency dependence of behavioral modulation by hippocampal electrical stimulation.

Electrical stimulation offers the potential to develop novel strategies for the treatment of refractory medial temporal lobe epilepsy. In particular, direct electrical stimulation of the hippocampus presents the opportunity to modulate pathological dynamics at the ictal focus, although the neuroanatomical substrate of this region renders it susceptible to altering cognition and affective processing as a side effect. We investigated the effects of three electrical stimulation paradigms on separate groups of freely moving rats (sham, 8-Hz and 40-Hz sine-wave stimulation of the ventral/intermediate hippocampus, where 8- and 40-Hz stimulation were chosen to mimic naturally occurring hippocampal oscillations). Animals exhibited attenuated locomotor and exploratory activity upon stimulation at 40 Hz, but not at sham or 8-Hz stimulation. Such behavioral modifications were characterized by a significant reduction in rearing frequency, together with increased freezing behavior. Logistic regression analysis linked the observed changes in animal locomotion to 40-Hz electrical stimulation independently of time-related variables occurring during testing. Spectral analysis, conducted to monitor the electrophysiological profile in the CA1 area of the dorsal hippocampus, showed a significant reduction in peak theta frequency, together with reduced theta power in the 40-Hz vs. the sham stimulation animal group, independent of locomotion speed (theta range: 4-12 Hz). These findings contribute to the development of novel and safe medical protocols by indicating a strategy to constrain or optimize parameters in direct hippocampal electrical stimulation.

An interaction between hepatocyte growth factor and its receptor (c-MET) prolongs the survival of chronic lymphocytic leukemic cells through STAT3 phosphorylation: a potential role of mesenchymal cells in the disease.

BACKGROUND: Chronic lymphocytic leukemia cells are characterized by an apparent longevity in vivo which is lost when they are cultured in vitro. Cellular interactions and factors provided by the microenvironment appear essential to cell survival and may protect leukemic cells from the cytotoxicity of conventional therapies. Understanding the cross-talk between leukemic cells and stroma is of interest for identifying signals supporting disease progression and for developing novel therapeutic strategies. DESIGN AND METHODS: Different cell types, sharing a common mesenchymal origin and representative of various bone marrow components, were used to challenge the viability of leukemic cells in co-cultures and in contact-free culture systems. Using a bioinformatic approach we searched for genes shared by lineages prolonging leukemic cell survival and further analyzed their biological role in signal transduction experiments. RESULTS: Human bone marrow stromal cells, fibroblasts, trabecular bone-derived cells and an osteoblast-like cell line strongly enhanced survival of leukemic cells, while endothelial cells and chondrocytes did not. Gene expression profile analysis indicated two soluble factors, hepatocyte growth factor and CXCL12, as potentially involved. We demonstrated that hepatocyte growth factor and CXCL12 are produced only by mesenchymal lineages that sustain the survival of leukemic cells. Indeed chronic lymphocytic leukemic cells express a functional hepatocyte growth factor receptor (c-MET) and hepatocyte growth factor enhanced the viability of these cells through STAT3 phosphorylation, which was blocked by a c-MET tyrosine kinase inhibitor. The role of hepatocyte growth factor was confirmed by its short interfering RNA-mediated knock-down in mesenchymal cells. CONCLUSIONS: The finding that hepatocyte growth factor prolongs the survival of chronic lymphocytic leukemic cells is novel and we suggest that the interaction between hepatocyte growth factor-producing mesenchymal and neoplastic cells contributes to maintenance of the leukemic clone.

Wnt5a is a transcriptional target of Dlx homeogenes and promotes differentiation of interneuron progenitors in vitro and in vivo.

During brain development, neurogenesis, migration, and differentiation of neural progenitor cells are regulated by an interplay between intrinsic genetic programs and extrinsic cues. The Dlx homeogene transcription factors have been proposed to directly control the genesis and maturation of GABAergic interneurons of the olfactory bulb (OB), subpallium, and cortex. Here we provide evidence that Dlx genes promote differentiation of olfactory interneurons via the signaling molecule Wnt5a. Dlx2 and Dlx5 interact with homeodomain binding sequences within the Wnt5a locus and activate its transcription. Exogenously provided Wnt5a promotes GABAergic differentiation in dissociated OB neurons and in organ-type brain cultures. Finally, we show that the Dlx-mutant environment is unfavorable for GABA differentiation, in vivo and in vitro. We conclude that Dlx genes favor interneuron differentiation also in a non-cell-autonomous fashion, via expression of Wnt5a.

Demethyl fruticulin A (SCO-1) causes apoptosis by inducing reactive oxygen species in mitochondria.

Demethyl fruticulin A (SCO-1) is a compound found in Salvia corrugata leaves. SCO-1 was reported to induce anoikis in cell lines via the membrane scavenging receptor CD36. However, experiments performed with cells lacking CD36 showed that SCO-1 was able to induce apoptosis also via alternative pathways. To gain some insight into the biological processes elicited by this compound, we undertook an unbiased genomic approach. Upon exposure of glioblastoma tumor initiating cells (GBM TICs) to SCO-1 for 24 h, we observed a deregulation of the genes belonging to the glutathione metabolism pathway and of those belonging to the biological processes related to the response to stress and to chemical stimulus. On this basis, we hypothesized that the SCO-1 killing effect could result from the induction of reactive oxygen species (ROS) in the mitochondria. This hypothesis was confirmed by flow cytometry using MitoSOX, a mitochondria-selective fluorescent reporter of ROS, and by the ability of N-acetyl cysteine (NAC) to inhibit apoptosis when co-administered with SOC-1 to the GBM TICs. We further show that NAC also protects other cell types such as HeLa, MG-63, and COS-7 from apoptosis. We therefore propose that ROS production is the major molecular mechanism responsible for the pro-apoptotic effect induced by SCO-1. Consequently, SCO-1 may have a potential therapeutic value, which deserves further investigation in animal models.

In vitro and in vivo characterization of highly purified human mesothelioma derived cells.

BACKGROUND: Malignant pleural mesothelioma is a rare disease known to be resistant to conventional therapies. A better understanding of mesothelioma biology may provide the rationale for new therapeutic strategies. In this regard, tumor cell lines development has been an important tool to study the biological properties of many tumors. However all the cell lines established so far were grown in medium containing at least 10% serum, and it has been shown that primary cell lines cultured under these conditions lose their ability to differentiate, acquire gene expression profiles that differ from that of tissue specific stem cells or the primary tumor they derive from, and in some cases are neither clonogenic nor tumorigenic. Our work was aimed to establish from fresh human pleural mesothelioma samples cell cultures maintaining tumorigenic properties. METHODS: The primary cell cultures, obtained from four human pleural mesotheliomas, were expanded in vitro in a low serum proliferation-permissive medium and the expression of different markers as well as the tumorigenicity in immunodeficient mice was evaluated. RESULTS: The established mesothelioma cell cultures are able to engraft, after pseudo orthotopic intraperitoneal transplantation, in immunodeficient mouse and maintain this ability to after serial transplantation. Our cell cultures were strongly positive for CD46, CD47, CD56 and CD63 and were also strongly positive for some markers never described before in mesothelioma cell lines, including CD55, CD90 and CD99. By real time PCR we found that our cell lines expressed high mRNA levels of typical mesothelioma markers as mesothelin (MSLN) and calretinin (CALB2), and of BMI-1, a stemness marker, and DKK1, a potent Wingless [WNT] inhibitor. CONCLUSIONS: These cell cultures may provide a valuable in vitro and in vivo model to investigate mesothelioma biology. The identification of new mesothelioma markers may be useful for diagnosis and/or prognosis of this neoplasia as well as for isolation of mesothelioma tumor initiating cells.

Gefitinib targets EGFR dimerization and ERK1/2 phosphorylation to inhibit pleural mesothelioma cell proliferation.

Altered EGFR activity is a causal factor for human tumor development, including malignant pleural mesotheliomas. The aim of the present study was the evaluation of the effects of Gefitinib on EGF-induced mesothelioma cell proliferation and the intracellular mechanisms involved. Cell proliferation, DNA synthesis and apoptosis were measured by MTT, thymidine incorporation and FACS analysis; EGFR, ERK1/2 and Akt expression and phosphorylation by Western blot, whereas receptor sites were analyzed by binding studies. Gefitinib inhibited EGF-induced proliferation in two mesothelioma cell lines, derived from pleural effusion (IST-Mes2) or tumor biopsy (ZL55). The treatment with Gefitinib induced cell cycle arrest in both cell lines, while apoptosis was observed only for high concentrations and prolonged drug exposure. EGF-dependent mesothelioma cell proliferation was mediated by EGFR and ERK1/2 phosphorylation, while Akt was not affected. Gefitinib inhibited both EGFR and ERK1/2 activation, being maximal at drug concentrations that induce cytostatic effects, suggesting that the proapoptotic activity of Gefitinib is independent from EGFR inhibition. Gefitinib treatment increased EGFR Bmax, possibly through membrane stabilization of inactive receptor dimers that we show to be induced by the drug also in the absence of EGF. EGFR activation of ERK1/2 represents a key pathway for pleural mesothelioma cell proliferation. Low concentrations of Gefitinib cause mesothelioma cell cycle arrest through the blockade of EGFR activity while high concentrations induce apoptosis. Finally, we propose that the formation of inactive EGFR dimers may contribute to the antitumoral activity of Gefitinib.

z-Leucinyl-leucinyl-norleucinal induces apoptosis of human glioblastoma tumor-initiating cells by proteasome inhibition and mitotic arrest response.

Gamma-secretase inhibitors have been proposed as drugs able to kill cancer cells by targeting the NOTCH pathway. Here, we investigated two of such inhibitors, the Benzyloxicarbonyl-Leu-Leu-Nle-CHO (LLNle) and the N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT), to assess whether they were effective in killing human glioblastoma tumor-initiating cells (GBM TIC) in vitro. We found that only LLNle was able at the micromolar range to induce the death of GBM TICs by apoptosis. To determine the cellular processes that were activated in GBM TICs by treatment with LLNle, we analyzed the amount of the NOTCH intracellular domain and the gene expression profiles following treatment with LLNle, DAPT, and DMSO (vehicle). We found that LLNIe, beside inhibiting the generation of the NOTCH intracellular domain, also induces proteasome inhibition, proteolytic stress, and mitotic arrest in these cells by repressing genes required for DNA synthesis and mitotic progression and by activating genes acting as mitotic inhibitors. DNA content flow cytometry clearly showed that cells treated with LLNle undergo arrest in the G(2)-M phases of the cell cycle. We also found that DAPT and L-685,458, another selective Notch inhibitor, were unable to kill GBM TICs, whereas lactacystin, a pure proteasome inhibitor, was effective although at a much less extent than LLNle. These data show that LLNle kills GBM TIC cells by inhibiting the proteasome activity. We suggest that LLNle, being able to target two relevant pathways for GBM TIC survival, may have a potential therapeutic value that deserves further investigation in animal models.

Comparative analysis of DNA repair in stem and nonstem glioma cell cultures.

It has been reported that cancer stem cells may contribute to glioma radioresistance through preferential activation of the DNA damage checkpoint response and an increase in DNA repair capacity. We have examined DNA repair in five stem and nonstem glioma cell lines. The population doubling time was significantly increased in stem compared with nonstem cells, and enhanced activation of Chk1 and Chk2 kinases was observed in untreated CD133(+) compared with CD133(-) cells. Neither DNA base excision or single-strand break repair nor resolution of pH2AX nuclear foci were increased in CD133(+) compared with CD133(-) cells. We conclude that glioma stem cells display elongated cell cycle and enhanced basal activation of checkpoint proteins that might contribute to their radioresistance, whereas enhanced DNA repair is not a common feature of these cells.

NK cells recognize and kill human glioblastoma cells with stem cell-like properties.

In this study, cancer cells were isolated from tumor specimens of nine glioblastoma patients. Glioblastoma cells, cultured under suitable culture conditions, displayed markers typical of neural stem cells, were capable of partial multilineage differentiation in vitro, and gave origin to infiltrating tumors when orthotopically injected in NOD/SCID mice. These cells, although resistant to freshly isolated NK cells, were highly susceptible to lysis mediated by both allogeneic and autologous IL-2 (or IL-15)-activated NK cells. Indeed, all stem cell-cultured glioblastoma cells analyzed did not express protective amounts of HLA class I molecules, while expressing various ligands of activating NK receptors that triggered optimal NK cell cytotoxicity. Importantly, glioblastoma stem cells expressed high levels of PVR and Nectin-2, the ligands of DNAM-1-activating NK receptor.

Different response of human glioma tumor-initiating cells to epidermal growth factor receptor kinase inhibitors.

Because a subpopulation of cancer stem cells (tumor-initiating cells, TICs) is believed to be responsible for the development, progression, and recurrence of many tumors, we evaluated the in vitro sensitivity of human glioma TICs to epidermal growth factor receptor (EGFR) kinase inhibitors (erlotinib and gefitinib) and possible molecular determinants for their effects. Cells isolated from seven glioblastomas (GBM 1-7) and grown using neural stem cell permissive conditions were characterized for in vivo tumorigenicity, expression of tumor stem cell markers (CD133, nestin), and multilineage differentiation properties, confirming that these cultures are enriched in TICs. TIC cultures were challenged with increasing concentrations of erlotinib and gefitinib, and their survival was evaluated after 1-4 days. In most cases, a time- and concentration-dependent cell death was observed, although GBM 2 was completely insensitive to both drugs, and GBM 7 was responsive only to the highest concentrations tested. Using a radioligand binding assay, we show that all GBM TICs express EGFR. Erlotinib and gefitinib inhibited EGFR and ERK1/2 phosphorylation/activation in all GBMs, irrespective of the antiproliferative response observed. However, under basal conditions GBM 2 showed a high Akt phosphorylation that was completely insensitive to both drugs, whereas GBM 7 was completely insensitive to gefitinib, and Akt inactivation occurred only for the highest erlotinib concentration tested, showing a precise relationship with the antiproliferative effects of the drug. Interestingly, in GBM 2, phosphatase and tensin homolog expression was significantly down-regulated, possibly accounting for the insensitivity to the drugs. In conclusion, glioma TICs are responsive to anti-EGFR drugs, but phosphatase and tensin homolog expression and Akt inhibition seem to be necessary for such effect.

PDGF-B induces a homogeneous class of oligodendrogliomas from embryonic neural progenitors.

We describe the generation of mouse gliomas following the overexpression of PDGF-B in embryonic neural progenitors. Our histopathological, immunohistochemical and genome-wide expression analyses revealed a surprising uniformity among PDGF-B induced tumors, despite they were generated by transducing a highly heterogeneous population of progenitor cells known for their ability to produce all the cell types of the central nervous system. Comparison of our microarray data with published gene expression data sets for many different murine neural cell types revealed a closest correlation between our tumor cells and oligodendrocyte progenitor cells, confirming definitively that PDGF-B-induced gliomas are pure oligodendrogliomas. Importantly, we show that this uniformity is likely due to the ability of PDGF-B overexpression to respecify competent embryonic neural precursors toward the oligodendroglial lineage, providing evidence that the transforming activity of PDGF-B is influenced by the developmental potential of the targeted cells. Interestingly, we found that PDGF-B-induced tumors harbor different proliferating cell populations. However only PDGF-B-overexpressing cells are tumorigenic, indicating that paracrine signaling from the tumor is unable to transform bystander cells.

SOX2 silencing in glioblastoma tumor-initiating cells causes stop of proliferation and loss of tumorigenicity.

Glioblastoma, the most aggressive cerebral tumor, is invariably lethal. Glioblastoma cells express several genes typical of normal neural stem cells. One of them, SOX2, is a master gene involved in sustaining self-renewal of several stem cells, in particular neural stem cells. To investigate its role in the aberrant growth of glioblastoma, we silenced SOX2 in freshly derived glioblastoma tumor-initiating cells (TICs). Our results indicate that SOX2 silenced glioblastoma TICs, despite the many mutations they have accumulated, stop proliferating and lose tumorigenicity in immunodeficient mice. SOX2 is then also fundamental for maintenance of the self-renewal capacity of neural stem cells when they have acquired cancer properties. SOX2, or its immediate downstream effectors, would then be an ideal target for glioblastoma therapy.

Tumor progression and oncogene addiction in a PDGF-B-induced model of gliomagenesis.

Platelet-derived growth factor B (PDGF-B) overexpression induces gliomas of different grades from murine embryonic neural progenitors. For the first time, we formally demonstrated that PDGF-B-induced neoplasms undergo progression from nontumorigenic low-grade tumors toward highly malignant forms. This result, showing that PDGF-B signaling alone is insufficient to confer malignancy to cells, entails the requirement for further molecular lesions in this process. Our results indicate that one of these lesions is represented by the down-regulation of the oncosuppressor Btg2. By in vivo transplantation assays, we further demonstrate that fully progressed tumors are PDGF-B-addicted because their tumor-propagating ability is lost when the PDGF-B transgene is silenced, whereas it is promptly reacquired after its reactivation. We provide evidence that this oncogene addiction is not caused by the need for PDGF-B as a mitogen but, rather, to the fact that PDGF-B is required to overcome cell-cell contact inhibition and to confer in vivo infiltrating potential on tumor cells.

The VGF-derived peptide TLQP-21: a new modulatory peptide for inflammatory pain.

Vgf, is a neuro-endocrine specific gene encoding for a large protein precursor of different peptides. A role for VGF in pain modulation has been suggested from immunohistochemical studies showing VGF mRNA widely expressed in primary sensory neurons. In this study, the presence of VGF on the primary sensory afferents in mice was confirmed by showing its immunostaining in cultured neurons of dorsal root ganglia in secretory granule varicosities colocalized with Substance P. Moreover, the functional role of a C-terminal internal VGF-derived peptide, i.e. TLQP-21, was assessed by investigating its peripheral (1, 2, 4, 8mM) and central (1, 2, 4 mM) effects on inflammatory pain in the formalin test. A significant increase of pain-related licking response following peripheral injection of TLQP-21 (4 and 8mM) was observed in the second inflammatory phase of the test. In addition, an increase in licking response was detected when 4 mM of the peptide was injected alone without formalin. On the other hand, the central administration of TLQP-21 induced an U-shaped curve, with the dose of 2 mM being analgesic during the second phase. This study shows for the first time that a VGF-derived peptide may be involved in inflammatory pain in vivo and demonstrates a different action for TLQP21 at the peripheral and central levels of the nociceptive pathways.

DLX5 overexpression impairs osteogenic differentiation of human bone marrow stromal cells.

The transcription factor DLX5 belongs to a family of homeoproteins required for craniofacial morphogenesis and forebrain development. DLX5 is expressed during formation of several skeletal elements such as cartilage, teeth and bone, and its knockout causes severe craniofacial malformations with a delay in the ossification process. Bone marrow contains mesenchymal progenitor cells which may differentiate along multiple pathways, therefore representing an interesting in vitro and in vivo model to study the mesodermal lineage differentiation. Here we report the effect of DLX5 overexpression in ex vivo expanded human bone marrow stromal cells by retroviral infection on the osteogenic lineage differentiation. A reduced mineral deposition was observed in DLX5-transduced cells upon osteogenic induction in culture. When DLX5-transduced cells were implanted in immunodeficient mice, a 60% reduction in bone matrix deposition was observed, whereas the in vitro chondrogenic potential was unaffected. A quantitative gene expression study indicated that DLX5 overexpression does not affect the early osteogenic commitment of bone marrow stromal cells but prevents their terminal differentiation. This block may be mediated by the observed persistent expression of SOX2, a transcription factor known to inhibit osteogenic differentiation.

MR and iron magnetic nanoparticles. Imaging opportunities in preclinical and translational research.

Ultrasmall superparamagnetic iron oxide nanoparticles and magnetic resonance imaging provide a non-invasive method to detect and label tumor cells. These nanoparticles exhibit unique properties of superparamagnetism and can be utilized as excellent probes for magnetic resonance imaging. Most work has been performed using a magnetic resonance scanner with high field strength up to 7 T. Ultrasmall superparamagnetic iron oxide nanoparticles may represent a suitable tool for labeling molecular probes that target specific tumor-associated markers for in vitro and in vivo detection by magnetic resonance imaging. In our study, we demonstrated that magnetic resonance imaging at 1.5 T allows the detection of ultrasmall superparamagnetic iron oxide nanoparticle conjugated antibody specifically bound to human tumor cells in vitro and in vivo, and that the magnetic resonance signal intensity correlates with the concentration of ultrasmall superparamagnetic iron oxide nanoparticle antibody used and with the antigen density at the cell surface. The experiments were performed using two different means of targeting: direct and indirect magnetic tumor targeting. The imaging of tumor antigens using immunospecific contrast agents is a rapidly evolving field, which can potentially aid in early disease detection, monitoring of treatment efficacy, and drug development. Cell labeling by iron oxide nanoparticles has emerged as a potentially powerful tool to monitor trafficking of a large number of cells in the cell therapy field. We also studied the labeling of natural killer cells with iron nanoparticles to a level that would allow the detection of their signal intensity with a clinical magnetic resonance scanner at 1.5 T. Magnetic resonance imaging and iron magnetic nanoparticles are able to increase the accuracy and the specificity of imaging and represent new imaging opportunities in preclinical and translational research.

Six3 controls the neural progenitor status in the murine CNS.

Six3, a homeodomain-containing transcriptional regulator belonging to the Six/so family, shows a defined spatiotemporal expression pattern in the developing murine telencephalon, suggesting that it may control the development of specific subsets of neural progenitors. We find that retrovirus-mediated misexpression of Six3 causes clonal expansion of isolated cortical progenitor cells by shortening their cell cycle and by prolonging their amplification period, while maintaining them in an immature precursor state. Our results show that the observed effects exerted by Six3 overexpression in mammalian brain depend strictly on the integrity of its DNA-binding domain, suggesting that Six3 action likely relies exclusively on its transcriptional activity. In vivo upregulation of Six3 expression in single progenitor cells of the embryonic telencephalon keeps them in an undifferentiated state. Our observations point to a role of Six3 in the control of the subtle equilibrium between proliferation and differentiation of defined precursor populations during mammalian neurogenesis.

Glioma immunotherapy by IL-21 gene-modified cells or by recombinant IL-21 involves antibody responses.

Most tumors of the central nervous system, especially glioblastoma, are refractory to treatment and invariably lethal. The aim of this study was to assess the ability of different interleukins (IL), IL-2, IL-12 and IL-21, produced by transduced glioma cells to activate an immune response and trigger intracranial tumor rejection. Such experiments were performed by the use of a slow-growing clone of GL261 (GL D2-60) that was used as orthotopic glioma model. Using GL D2-60-transduced cells, all cytokines elicited an immune response against the tumor. Most notably 100% of the animals receiving a primary implant of IL-21-transduced cells rejected the implant, and 76% of these animals survived to a subsequent rechallenge with GL261 parental cells, while the other transduced cytokine genes were not as effective. Rejection responses were also obtained by admixing wild-type tumor cells with IL-21-producing GL D2-60 cells, indicating a local bystander effect of IL-21. More importantly, IL-21-secreting GL D2-60 cells or 1 microg of rIL-21 protein stereotactically injected into established GL D2-60 tumors were able to trigger glioblastoma rejection in 90 and 77% of mice, respectively. Again most of these mice survived to GL261 rechallenge. Immune mice showed antibody responses to glioma antigens, predominantly involving IgG2a and IgG2b isotypes, which mediated complement- or cell-dependent glioma cell lysis. Antibody responses were crucial for glioma immunotherapy by IL-21-secreting GL D2-60 cells, as immunotherapy was uneffective in syngeneic microMT B-cell-deficient mice. These results suggest that IL-21 should be considered as a suitable candidate for glioma immunotherapy by local delivery.

Identification of a set of KSRP target transcripts upregulated by PI3K-AKT signaling.

BACKGROUND: KSRP is a AU-rich element (ARE) binding protein that causes decay of select sets of transcripts in different cell types. We have recently described that phosphatidylinositol 3-kinase/AKT (PI3K-AKT) activation induces stabilization and accumulation of the labile beta-catenin mRNA through an impairment of KSRP function. RESULTS: Aim of this study was to identify additional KSRP targets whose stability and steady-state levels are enhanced by PI3K-AKT activation. First, through microarray analyses of the AU-rich transcriptome in pituitary alphaT3-1 cells, we identified 34 ARE-containing transcripts upregulated in cells expressing a constitutively active form of AKT1. In parallel, by an affinity chromatography-based technique followed by microarray analyses, 12 mRNAs target of KSRP, additional to beta-catenin, were identified. Among them, seven mRNAs were upregulated in cells expressing activated AKT1. Both steady-state levels and stability of these new KSRP targets were consistently increased by either KSRP knock-down or PI3K-AKT activation. CONCLUSION: Our study identified a set of transcripts that are targets of KSRP and whose expression is increased by PI3K-AKT activation. These mRNAs encode RNA binding proteins, signaling molecules and a replication-independent histone. The increased expression of these gene products upon PI3K-AKT activation could play a role in the cellular events initiated by this signaling pathway.