Publications by authors named "Francesca Buontempo"

23 Publications

  • Page 1 of 1

Enhancing radiosensitivity of melanoma cells through very high dose rate pulses released by a plasma focus device.

PLoS One 2018 29;13(6):e0199312. Epub 2018 Jun 29.

University of Bologna, Department of Physics and Astronomy, Bologna, Italy.

Radiation therapy is a useful and standard tumor treatment strategy. Despite recent advances in delivery of ionizing radiation, survival rates for some cancer patients are still low because of recurrence and radioresistance. This is why many novel approaches have been explored to improve radiotherapy outcome. Some strategies are focused on enhancement of accuracy in ionizing radiation delivery and on the generation of greater radiation beams, for example with a higher dose rate. In the present study we proposed an in vitro research of the biological effects of very high dose rate beam on SK-Mel28 and A375, two radioresistant human melanoma cell lines. The beam was delivered by a pulsed plasma device, a "Mather type" Plasma Focus for medical applications. We hypothesized that this pulsed X-rays generator is significantly more effective to impair melanoma cells survival compared to conventional X-ray tube. Very high dose rate treatments were able to reduce clonogenic efficiency of SK-Mel28 and A375 more than the X-ray tube and to induce a greater, less easy-to-repair DNA double-strand breaks. Very little is known about biological consequences of such dose rate. Our characterization is preliminary but is the first step toward future clinical considerations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0199312PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6025851PMC
April 2019

Marine bisindole alkaloid: A potential apoptotic inducer in human cancer cells.

Eur J Histochem 2018 Apr 10;62(2):2881. Epub 2018 Apr 10.

University of Urbino, Department of Biomolecular Sciences.

Marine organisms such as corals, sponges and tunicates produce active molecules which could represent a valid starting point for new drug development processes. Among the various structural classes, the attention has been focused on 2,2-bis(6-bromo-3-indolyl) ethylamine, a marine alkaloid which showed a good anticancer activity against several tumor cell lines. Here, for the first time, the mechanisms of action of 2,2-bis(6-bromo-3-indolyl) ethylamine have been evaluated in a U937 tumor cell model. Morpho-functional and molecular analyses, highlighting its preferred signaling pathway, demonstrated that apoptosis is the major death response induced by this marine compund. Chromatin condensation, micronuclei formation, blebbing and in situ DNA fragmentation, occurring through caspase activation (extrinsic and intrinsic pathways), were observed. In particular, the bisindole alkaloid induces a mitochondrial involvement in apoptosis machinery activation with Blc-2/Bcl-x down-regulation and Bax up-regulation. These findings demonstrated that 2,2-bis(6-bromo-3-indolyl) ethylamine alkaloid-induced apoptosis is regulated by the Bcl-2 protein family upstream of caspase activation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4081/ejh.2018.2881DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6038113PMC
April 2018

Drug discovery targeting the mTOR pathway.

Clin Sci (Lond) 2018 03 9;132(5):543-568. Epub 2018 Mar 9.

Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC 27858, U.S.A.

Mechanistic target of rapamycin (mTOR) is the kinase subunit of two structurally and functionally distinct large multiprotein complexes, referred to as mTOR complex 1 (mTORC1) and mTORC2. mTORC1 and mTORC2 play key physiological roles as they control anabolic and catabolic processes in response to external cues in a variety of tissues and organs. However, mTORC1 and mTORC2 activities are deregulated in widespread human diseases, including cancer. Cancer cells take advantage of mTOR oncogenic signaling to drive their proliferation, survival, metabolic transformation, and metastatic potential. Therefore, mTOR lends itself very well as a therapeutic target for innovative cancer treatment. mTOR was initially identified as the target of the antibiotic rapamycin that displayed remarkable antitumor activity Promising preclinical studies using rapamycin and its derivatives (rapalogs) demonstrated efficacy in many human cancer types, hence supporting the launch of numerous clinical trials aimed to evaluate the real effectiveness of mTOR-targeted therapies. However, rapamycin and rapalogs have shown very limited activity in most clinical contexts, also when combined with other drugs. Thus, novel classes of mTOR inhibitors with a stronger antineoplastic potency have been developed. Nevertheless, emerging clinical data suggest that also these novel mTOR-targeting drugs may have a weak antitumor activity. Here, we summarize the current status of available mTOR inhibitors and highlight the most relevant results from both preclinical and clinical studies that have provided valuable insights into both their efficacy and failure.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1042/CS20171158DOI Listing
March 2018

Protective effect of different antioxidant agents in UVB-irradiated keratinocytes.

Eur J Histochem 2017 Sep 18;61(3):2784. Epub 2017 Sep 18.

University of Urbino "Carlo Bo".

Skin cells can respond to UVB-induced damage either by tolerating it, or restoring it through antioxidant activation and DNA repair mechanisms or, ultimately, undergoing programmed cell death, when damage is massive. Nutritional factors, in particular, food antioxidants, have attracted much interest because of their potential use in new preventive, protective, and therapeutic strategies for chronic degenerative diseases, including skin inflammation and cancer. Some polyphenols, present in virgin olive oil, well tolerated by organism after oral administration, show a variety of pharmacological and clinical benefits such as anti-oxidant, anti-cancer, anti-inflammatory, and neuro-protective activities. Here, the protective effects of antioxidant compounds against UV-induced apoptosis have been described in HaCat cell line. Human keratinocytes were pre-treated with antioxidants before UVB exposure and their effects have been evaluated by means of ultrastructural analyses. After UVB radiation, a known cell death trigger, typical apoptotic features, absent in control condition and in antioxidant alone-treated cells, appear. An evident numerical decrease of ultrastructural apoptotic patterns and TUNEL positive nuclei can be observed when natural antioxidants were supplied before cell death induction. These data have been confirmed by molecular investigation of caspase activity. In conclusion, this paper highlights antioxidant compound ability to prevent apoptotic cell death in human keratinocytes exposed to UVB, suggesting, for these molecules, a potential role in preventing skin damage.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4081/ejh.2017.2784DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5617901PMC
September 2017

Phosphatidylinositol 3-kinase inhibition potentiates glucocorticoid response in B-cell acute lymphoblastic leukemia.

J Cell Physiol 2018 Mar 7;233(3):1796-1811. Epub 2017 Sep 7.

Institute of Molecular Genetics, Rizzoli Orthopedic Institute, National Research Council, Bologna, Italy.

Despite remarkable progress in polychemotherapy protocols, pediatric B-cell acute lymphoblastic leukemia (B-ALL) remains fatal in around 20% of cases. Hence, novel targeted therapies are needed for patients with poor prognosis. Glucocorticoids (GCs) are drugs commonly administrated for B-ALL treatment. Activation of the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin signaling pathway is frequently observed in B-ALL and contributes to GC-resistance. Here, we analyzed for the first time to our knowledge, the therapeutic potential of pan and isoform-selective PI3K p110 inhibitors, alone or combined with dexamethasone (DEX), in B-ALL leukemia cell lines and patient samples. We found that a pan PI3K p110 inhibitor displayed the most powerful cytotoxic effects in B-ALL cells, by inducing cell cycle arrest and apoptosis. Both a pan PI3K p110 inhibitor and a dual γ/δ PI3K p110 inhibitor sensitized B-ALL cells to DEX by restoring nuclear translocation of the GC receptor and counteracted stroma-induced DEX-resistance. Finally, gene expression analysis documented that, on one hand the combination consisting of a pan PI3K p110 inhibitor and DEX strengthened the DEX-induced up- or down-regulation of several genes involved in apoptosis, while on the other, it rescued the effects of genes that might be involved in GC-resistance. Overall, our findings strongly suggest that PI3K p110 inhibition could be a promising strategy for treating B-ALL patients by improving GC therapeutic effects and/or overcoming GC-resistance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jcp.26135DOI Listing
March 2018

Improving nelarabine efficacy in T cell acute lymphoblastic leukemia by targeting aberrant PI3K/AKT/mTOR signaling pathway.

J Hematol Oncol 2016 10 24;9(1):114. Epub 2016 Oct 24.

Institute of Molecular Genetics, Rizzoli Orthopedic Institute, National Research Council, Bologna, Italy.

Background: Although in recent years, the introduction of novel chemotherapy protocols has improved the outcome of T cell acute lymphoblastic leukemia (T-ALL) patients, refractory and/or relapsing disease remains a foremost concern. In this context, a major contribution was provided by the introduction of the nucleoside analog nelarabine, approved for salvage treatment of T-ALL patients with refractory/relapsed disease. However, nelarabine could induce a life-threatening, dose-dependent neurotoxicity. To improve nelarabine efficacy, we have analyzed its molecular targets, testing selective inhibitors of such targets in combination with nelarabine.

Methods: The effectiveness of nelarabine as single agent or in combination with PI3K, Bcl2, and MEK inhibitors was evaluated on human T-ALL cell lines and primary T-ALL refractory/relapsed lymphoblasts. The efficacy of signal modulators in terms of cytotoxicity, induction of apoptosis, and changes in gene and protein expression was assessed by flow cytometry, western blotting, and quantitative real-time PCR in T-ALL settings.

Results: Treatment with nelarabine as a single agent identified two groups of T-ALL cell lines, one sensitive and one resistant to the drug. Whereas sensitive T-ALL cells showed a significant increase of apoptosis and a strong down-modulation of PI3K signaling, resistant T-ALL cells showed a hyperactivation of AKT and MEK/ERK1/2 signaling pathways, not caused by differences in the expression of nelarabine transporters or metabolic activators. We then studied the combination of nelarabine with the PI3K inhibitors (both pan and dual γ/δ inhibitors), with the Bcl2 specific inhibitor ABT199, and with the MEK inhibitor trametinib on both T-ALL cell lines and patient samples at relapse, which displayed constitutive activation of PI3K signaling and resistance to nelarabine alone. The combination with the pan PI3K inhibitor ZSTK-474 was the most effective in inhibiting the growth of T-ALL cells and was synergistic in decreasing cell survival and inducing apoptosis in nelarabine-resistant T-ALL cells. The drug combination caused AKT dephosphorylation and a downregulation of Bcl2, while nelarabine alone induced an increase in p-AKT and Bcl2 signaling in the resistant T-ALL cells and relapsed patient samples.

Conclusions: These findings indicate that nelarabine in combination with PI3K inhibitors may be a promising therapeutic strategy for the treatment of T-ALL relapsed patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13045-016-0344-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5075755PMC
October 2016

Synergistic cytotoxic effects of bortezomib and CK2 inhibitor CX-4945 in acute lymphoblastic leukemia: turning off the prosurvival ER chaperone BIP/Grp78 and turning on the pro-apoptotic NF-κB.

Oncotarget 2016 Jan;7(2):1323-40

Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.

The proteasome inhibitor bortezomib is a new targeted treatment option for refractory or relapsed acute lymphoblastic leukemia (ALL) patients. However, a limited efficacy of bortezomib alone has been reported. A terminal pro-apoptotic endoplasmic reticulum (ER) stress/unfolded protein response (UPR) is one of the several mechanisms of bortezomib-induced apoptosis. Recently, it has been documented that UPR disruption could be considered a selective anti-leukemia therapy. CX-4945, a potent casein kinase (CK) 2 inhibitor, has been found to induce apoptotic cell death in T-ALL preclinical models, via perturbation of ER/UPR pathway. In this study, we analyzed in T- and B-ALL preclinical settings, the molecular mechanisms of synergistic apoptotic effects observed after bortezomib/CX-4945 combined treatment. We demonstrated that, adding CX-4945 after bortezomib treatment, prevented leukemic cells from engaging a functional UPR in order to buffer the bortezomib-mediated proteotoxic stress in ER lumen. We documented that the combined treatment decreased pro-survival ER chaperon BIP/Grp78 expression, via reduction of chaperoning activity of Hsp90. Bortezomib/CX-4945 treatment inhibited NF-κB signaling in T-ALL cell lines and primary cells from T-ALL patients, but, intriguingly, in B-ALL cells the drug combination activated NF-κB p65 pro-apoptotic functions. In fact in B-cells, the combined treatment induced p65-HDAC1 association with consequent repression of the anti-apoptotic target genes, Bcl-xL and XIAP. Exposure to NEMO (IKKγ)-binding domain inhibitor peptide reduced the cytotoxic effects of bortezomib/CX-4945 treatment. Overall, our findings demonstrated that CK2 inhibition could be useful in combination with bortezomib as a novel therapeutic strategy in both T- and B-ALL.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.18632/oncotarget.6361DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4811463PMC
January 2016

Advances in understanding the acute lymphoblastic leukemia bone marrow microenvironment: From biology to therapeutic targeting.

Biochim Biophys Acta 2016 Mar 1;1863(3):449-463. Epub 2015 Sep 1.

Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy. Electronic address:

The bone marrow (BM) microenvironment regulates the properties of healthy hematopoietic stem cells (HSCs) localized in specific niches. Two distinct microenvironmental niches have been identified in the BM, the "osteoblastic (endosteal)" and "vascular" niches. Nevertheless, these niches provide sanctuaries where subsets of leukemic cells escape chemotherapy-induced death and acquire a drug-resistant phenotype. Moreover, it is emerging that leukemia cells are able to remodel the BM niches into malignant niches which better support neoplastic cell survival and proliferation. This review focuses on the cellular and molecular biology of microenvironment/leukemia interactions in acute lymphoblastic leukemia (ALL) of both B- and T-cell lineage. We shall also highlight the emerging role of exosomes/microvesicles as efficient messengers for cell-to-cell communication in leukemia settings. Studies on the interactions between the BM microenvironment and ALL cells have led to the discovery of potential therapeutic targets which include cytokines/chemokines and their receptors, adhesion molecules, signal transduction pathways, and hypoxia-related proteins. The complex interplays between leukemic cells and BM microenvironment components provide a rationale for innovative, molecularly targeted therapies, designed to improve ALL patient outcome. A better understanding of the contribution of the BM microenvironment to the process of leukemogenesis and leukemia persistence after initial remission, may provide new targets that will allow destruction of leukemia cells without adversely affecting healthy HSCs. This article is part of a Special Issue entitled: Tumor Microenvironment Regulation of Cancer Cell Survival, Metastasis,Inflammation, and Immune Surveillance edited by Peter Ruvolo and Gregg L. Semenza.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bbamcr.2015.08.015DOI Listing
March 2016

Estrogen-deficient osteoporosis enhances the recruitment and activity of osteoclasts by breast cancer cells.

Histol Histopathol 2016 Jan 7;31(1):83-93. Epub 2015 Aug 7.

Laboratory of Biocompatibility, Technological Innovations and Advanced Therapies, Rizzoli Research Innovation Technology Department, and Laboratory of Preclinical and Surgical Studies, Rizzoli Orthopaedic Institute, Bologna, Italy.

To reduce the burden of bone metastases, the pathophysiology of the metastatic niche should be elucidated and targeted. The aim of the present study was to assess the effect of tumor cells on osteoclast (OC) recruitment and activity in the presence of altered bone remodelling. Peripheral blood mononuclear cells (PBMC) were isolated from healthy and ovariectomized (OVX) rats and co-cultured with MRMT-1 rat breast carcinoma cells or with their conditioned medium for 1 and 2 weeks. Alamar Blue viability test, synthesis of cathepsin K, transforming growth factor-beta 1 (TGF-β1), tumor necrosis factor alpha (TNF-α), vascular endothelial growth factor (VEGF), metalloproteinase (MMP)-7, MMP-9, FITC-conjugate phalloidin staining and tartrate-resistant acid phosphatase (TRAP) staining were evaluated. The results indicate that breast carcinoma cells induced different responses in PBMC derived from rats affected by estrogen deficiency osteoporosis (OP) in comparison with healthy ones, with a significant increase in proliferation rate, OC differentiation, synthesis of TNF-α, MMP-7 and MMP-9. The data support the "proof of concept" that OP due to estrogen deficiency might offer a receptive site for cancer cells to form bone metastases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.14670/HH-11-651DOI Listing
January 2016

Tyrosol prevents apoptosis in irradiated keratinocytes.

J Dermatol Sci 2015 Oct 6;80(1):61-8. Epub 2015 Jul 6.

DiSTeVA, University of Urbino Carlo Bo, Urbino 61029, Italy.

Background: Phenolic compounds, the biggest group of natural antioxidants, have attracted much attention due to their known and wide-ranging biological activities, as well as to their health effects. In particular, regardless their antioxidant activity, they play a key role in the control of several inflammation-associated processes as well as in improving antioxidant defense system. In an our previous work we have demonstrated the ability of Hydroxytyrosol, an ortho-diphenolic compound, essential component of oleuropein, in preventing apoptotic cell death induced by UVB radiation in HaCaT cell lines in vitro. In olive oil, besides Hydroxytyrosol, there are appreciable amounts of Tyrosol and its secoiridoid derivatives.

Objective: It has been well established that Tyrosol has a significantly lower antioxidant activity than Hydroxytyrosol, but despite this, recent studies suggest that Tyrosol exerts a powerful protective effect against oxidative injuries in cell systems and that it is able to improve the intracellular antioxidant defenses.

Materials And Methods: Here, Tyrosol effect has been evaluated in HaCaT cells exposed to UVB radiation by means of morphological and molecular analyses.

Results: Our study revealed the polyphenol ability in reducing apoptotic markers and in protecting HaCaT cells from damage.

Conclusion: These findings suggest an important role of Tyrosol in protecting cells from apoptotic cell death and encourage the use of this phytochemical as biological ingredient in topical preparations as possible tool to prevent skin damage.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jdermsci.2015.07.002DOI Listing
October 2015

PI3K pan-inhibition impairs more efficiently proliferation and survival of T-cell acute lymphoblastic leukemia cell lines when compared to isoform-selective PI3K inhibitors.

Oncotarget 2015 Apr;6(12):10399-414

Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.

Class I phosphatidylinositol 3-kinases (PI3Ks) are frequently activated in T-cell acute lymphoblastic leukemia (T-ALL), mainly due to the loss of PTEN function. Therefore, targeting PI3Ks is a promising innovative approach for T-ALL treatment, however at present no definitive evidence indicated which is the better therapeutic strategy between pan or selective isoform inhibition, as all the four catalytic subunits might participate in leukemogenesis. Here, we demonstrated that in both PTEN deleted and PTEN non deleted T-ALL cell lines, PI3K pan-inhibition exerted the highest cytotoxic effects when compared to both selective isoform inhibition or dual p110γ/δ inhibition. Intriguingly, the dual p110γ/δ inhibitor IPI-145 was effective in Loucy cells, which are representative of early T-precursor (ETP)-ALL, a T-ALL subtype associated with a poor outcome. PTEN gene deletion did not confer a peculiar reliance of T-ALL cells on PI3K activity for their proliferation/survival, as PTEN was inactivated in PTEN non deleted cells, due to posttranslational mechanisms. PI3K pan-inhibition suppressed Akt activation and induced caspase-independent apoptosis. We further demonstrated that in some T-ALL cell lines, autophagy could exert a protective role against PI3K inhibition. Our findings strongly support clinical application of class I PI3K pan-inhibitors in T-ALL treatment, with the possible exception of ETP-ALL cases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4496363PMC
http://dx.doi.org/10.18632/oncotarget.3295DOI Listing
April 2015

Antioxidants in the prevention of UVB-induced keratynocyte apoptosis.

J Photochem Photobiol B 2014 Dec 16;141:1-9. Epub 2014 Sep 16.

DiSTeVA, University of Urbino Carlo Bo, Urbino 61029, Italy.

Skin cells can respond to UVB-induced damage by counteracting it through antioxidant activation and DNA repair mechanisms or, when damage is massive by undergoing programmed cell death. Antioxidant factors, and, in particular, food compounds, have attracted much interest because of their potential use in new protective strategies for degenerative skin disorders. Melatonin, creatine and hydroxytyrosol show a variety of pharmacological and clinical benefits including anti-oxidant and anti-inflammatory activities. Here, the potential protective actions of antioxidant compounds against UVB-induced apoptosis were investigated in human keratinocytes. The cells were pre-treated with antioxidants before UVB exposure and their effect evaluated by means of ultrastructural and molecular analyses. After UVB radiation typical morphological apoptotic features and in situ DNA fragmentation after TUNEL reaction, appeared. A significant numerical decrease of apoptotic patterns could be observed when antioxidants were administrated before cell death induction. Moreover, both the intrinsic and extrinsic apoptotic pathways appeared activated after UVB radiation, and their down-regulation has been shown when antioxidants were added to cells before death induction. In conclusion, these compounds are able to prevent apoptotic cell death in human keratinocytes exposed to UVB, suggesting, for these molecules, an important role in preventing skin damage.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jphotobiol.2014.09.004DOI Listing
December 2014

Autophagy in acute leukemias: a double-edged sword with important therapeutic implications.

Biochim Biophys Acta 2015 Jan 2;1853(1):14-26. Epub 2014 Oct 2.

Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy. Electronic address:

Macroautophagy, usually referred to as autophagy, is a degradative pathway wherein cytoplasmatic components such as aggregated/misfolded proteins and organelles are engulfed within double-membrane vesicles (autophagosomes) and then delivered to lysosomes for degradation. Autophagy plays an important role in the regulation of numerous physiological functions, including hematopoiesis, through elimination of aggregated/misfolded proteins, and damaged/superfluous organelles. The catabolic products of autophagy (amino acids, fatty acids, nucleotides) are released into the cytosol from autophagolysosomes and recycled into bio-energetic pathways. Therefore, autophagy allows cells to survive starvation and other unfavorable conditions, including hypoxia, heat shock, and microbial pathogens. Nevertheless, depending upon the cell context and functional status, autophagy can also serve as a death mechanism. The cohort of proteins that constitute the autophagy machinery function in a complex, multistep biochemical pathway which has been partially identified over the past decade. Dysregulation of autophagy may contribute to the development of several disorders, including acute leukemias. In this kind of hematologic malignancies, autophagy can either act as a chemo-resistance mechanism or have tumor suppressive functions, depending on the context. Therefore, strategies exploiting autophagy, either for activating or inhibiting it, could find a broad application for innovative treatment of acute leukemias and could significantly contribute to improved clinical outcomes. These aspects are discussed here after a brief introduction to the autophagic molecular machinery and its roles in hematopoiesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bbamcr.2014.09.023DOI Listing
January 2015

Therapeutic potential of targeting mTOR in T-cell acute lymphoblastic leukemia (review).

Int J Oncol 2014 Sep 26;45(3):909-18. Epub 2014 Jun 26.

Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.

T-cell acute lymphoblastic leukemia (T-ALL) is a heterogeneous neoplastic disorder of immature hematopoietic precursors committed to the T-cell lineage. T-ALL comprises about 15% of pediatric and 25% of adult ALL cases. Even if the prognosis of T-ALL has improved especially in the childhood due to the use of new intensified treatment protocols, the outcome of relapsed patients who are resistant to conventional chemotherapeutic drugs or who relapse is still poor. For this reason, there is a need for novel and less toxic targeted therapies against signaling pathways aberrantly activated in T-ALL, such as the phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR). Small molecules designed to target key components of this signaling axis have proven their efficacy both in vitro and in vivo in pre-clinical settings of T-ALL. In particular, different classes of mTOR inhibitors have been disclosed by pharmaceutical companies, and they are currently being tested in clinical trials for treating T-ALL patients. One of the most promising approaches for the treatment of T-ALL seems to be the combination of mTOR inhibitors with traditional chemotherapeutic agents. This could lead to a lower drug dosage that may circumvent the systemic side effects of chemotherapeutics. In this review, we focus on the different classes of mTOR inhibitors that will possibly have an impact on the therapeutic arsenal we have at our disposal against T-ALL.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3892/ijo.2014.2525DOI Listing
September 2014

Targeting signaling pathways in T-cell acute lymphoblastic leukemia initiating cells.

Adv Biol Regul 2014 Sep 30;56:6-21. Epub 2014 Apr 30.

Institute of Molecular Genetics, National Research Council, via di Barbiano 1/10, 40136 Bologna, Italy; Musculoskeletal Cell Biology Laboratory, IOR, via di Barbiano 1/10, 40136 Bologna, Italy.

Leukemia initiating cells (LICs) represent a reservoir that is believed to drive relapse and resistance to chemotherapy in blood malignant disorders. T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive neoplastic disorder of immature hematopoietic precursors committed to the T-cell lineage. T-ALL comprises about 15% of pediatric and 25% of adult ALL cases and is prone to early relapse. Although the prognosis of T-ALL has improved especially in children due to the use of new intensified treatment protocols, the outcome of relapsed T-ALL cases is still poor. Putative LICs have been identified also in T-ALL. LICs are mostly quiescent and for this reason highly resistant to chemotherapy. Therefore, they evade treatment and give rise to disease relapse. At present great interest surrounds the development of targeted therapies against signaling networks aberrantly activated in LICs and important for their survival and drug-resistance. Both the Notch1 pathway and the phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) network are involved in T-ALL LIC survival and drug-resistance and could be targeted by small molecules. Thus, Notch1 and PI3K/Akt/mTOR inhibitors are currently being developed for clinical use either as single agents or in combination with conventional chemotherapy for T-ALL patient treatment. In this review, we summarize the existing knowledge of the relevance of Notch1 and PI3K/Akt/mTOR signaling in T-ALL LICs and we examine the rationale for targeting these key signal transduction networks by means of selective pharmacological inhibitors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jbior.2014.04.004DOI Listing
September 2014

GSK-3β: a key regulator of breast cancer drug resistance.

Cell Cycle 2014 4;13(5):697-8. Epub 2014 Feb 4.

Institute of Molecular Genetics; National Research Council; Bologna, Italy; Muscoloskeletal Cell Biology Laboratory; IOR; Bologna, Italy.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4161/cc.28091DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3979905PMC
May 2015

Targeting phosphatidylinositol 3-kinase signaling in acute myelogenous leukemia.

Expert Opin Ther Targets 2013 Aug 11;17(8):921-36. Epub 2013 Jun 11.

Institute of Molecular Genetics, National Research Council-Rizzoli Orthopedic Institute, Bologna, Italy.

Introduction: Despite continuous advances in our knowledge of the biology of acute myelogenous leukemia (AML), the prognosis of AML patients treated with standard chemotherapy is still poor, especially in the elderly. Therefore, there is a need for novel targeted and less toxic therapies, particularly for patients who develop resistance to traditional chemotherapeutic drugs. Constitutively active phosphatidylinositol 3-kinase (PI3K) signaling characterizes many types of tumors, including AML, where it negatively influences response to therapeutic treatments.

Areas Covered: The literature data showed that small inhibitor molecules targeting PI3K signaling induced cell cycle arrest, apoptosis and decreased drug-resistance in AML cells. PI3K inhibitors were also capable of targeting leukemic initiating cells (LICs), the most relevant target for leukemia eradication, whereas they tended to spare healthy hematopoietic stem cells.

Expert Opinion: Data emerging from pre-clinical settings suggest that the PI3K pathway is critically involved in regulating proliferation, survival and drug-resistance of AML cells. Therefore, we propose that novel drugs targeting this signaling pathway may offer a novel and less toxic treatment option for AML patients, most likely in combination with a lower dosage of traditional chemotherapeutic agents or other innovative therapeutic agents.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1517/14728222.2013.808333DOI Listing
August 2013

Harnessing the PI3K/Akt/mTOR pathway in T-cell acute lymphoblastic leukemia: eliminating activity by targeting at different levels.

Oncotarget 2012 Aug;3(8):811-23

Department of Human Anatomy, University of Bologna, Bologna, Italy.

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignant hematological disorder arising in the thymus from T-cell progenitors. T-ALL mainly affects children and young adults, and remains fatal in 20% of adolescents and 50% of adults, despite progress in polychemotherapy protocols. Therefore, innovative targeted therapies are desperately needed for patients with a dismal prognosis. Aberrant activation of PI3K/Akt/mTOR signaling is a common event in T-ALL patients and portends a poor prognosis. Preclinical studies have highlighted that modulators of PI3K/Akt/mTOR signaling could have a therapeutic relevance in T-ALL. However, the best strategy for inhibiting this highly complex signal transduction pathway is still unclear, as the pharmaceutical companies have disclosed an impressive array of small molecules targeting this signaling network at different levels. Here, we demonstrate that a dual PI3K/PDK1 inhibitor, NVP-BAG956, displayed the most powerful cytotoxic affects against T-ALL cell lines and primary patients samples, when compared with a pan class I PI3K inhibitor (GDC-0941), an allosteric Akt inhibitor (MK-2206), an mTORC1 allosteric inhibitor (RAD-001), or an ATP-competitive mTORC1/mTORC2 inhibitor (KU63794). Moreover, we also document that combinations of some of the aforementioned drugs strongly synergized against T-ALL cells at concentrations well below their respective IC50. This observation indicates that vertical inhibition at different levels of the PI3K/Akt/mTOR network could be considered as a future innovative strategy for treating T-ALL patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3478458PMC
http://dx.doi.org/10.18632/oncotarget.579DOI Listing
August 2012

Activity of the selective IκB kinase inhibitor BMS-345541 against T-cell acute lymphoblastic leukemia: involvement of FOXO3a.

Cell Cycle 2012 Jul 1;11(13):2467-75. Epub 2012 Jul 1.

Laboratory of Preclinical and Surgical Studies, Rizzoli Orthopedic Institute, Bologna, Italy.

Several lines of evidence suggest that the IκB kinase (IKK)/nuclear factor-κB (NFκB) axis is required for viability of leukemic cells and is a predictor of relapse in T-cell acute lymphoblastic leukemia (T-ALL). Moreover, many anticancer agents induce NFκB nuclear translocation and activation of its target genes, which counteract cellular resistance to chemotherapeutic drugs. Therefore, the design and the study of IKK-specific drugs is crucial to inhibit tumor cell proliferation and to prevent cancer drug-resistance. Here, we report the anti-proliferative effects induced by BMS-345541 (a highly selective IKK inhibitor) in three Notch1-mutated T-ALL cell lines and in T-ALL primary cells from pediatric patients. BMS-345541 induced apoptosis and an accumulation of cells in the G 2/M phase of the cell cycle via inhibition of IKK/NFκB signaling. We also report that T-ALL cells treated with BMS-345541 displayed nuclear translocation of FOXO3a and restoration of its functions, including control of p21(Cip1) expression levels. We demonstrated that FOXO3a subcellular re-distribution is independent of AKT and ERK 1/2 signaling, speculating that in T-ALL the loss of FOXO3a tumor suppressor function could be due to deregulation of IKK, as has been previously demonstrated in other cancer types. It is well known that, differently from p53, FOXO3a mutations have not yet been found in human tumors, which makes therapeutics activating FOXO3a more appealing than others. For these features, BMS-345541 could be used alone or in combination with traditional therapies in the treatment of T-ALL.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4161/cc.20859DOI Listing
July 2012

Two hits are better than one: targeting both phosphatidylinositol 3-kinase and mammalian target of rapamycin as a therapeutic strategy for acute leukemia treatment.

Oncotarget 2012 Apr;3(4):371-94

Department of Human Anatomy, University of Bologna, Cellular Signalling Laboratory, Bologna, Italy.

Phosphatidylinositol 3-kinase (PI3K) and mammalian target of rapamycin (mTOR) are two key components of the PI3K/Akt/mTOR signaling pathway. This signal transduction cascade regulates a wide range of physiological cell processes, that include differentiation, proliferation, apoptosis, autophagy, metabolism, motility, and exocytosis. However, constitutively active PI3K/Akt/mTOR signaling characterizes many types of tumors where it negatively influences response to therapeutic treatments. Hence, targeting PI3K/Akt/mTOR signaling with small molecule inhibitors may improve cancer patient outcome. The PI3K/Akt/mTOR signaling cascade is overactive in acute leukemias, where it correlates with enhanced drug-resistance and poor prognosis. The catalytic sites of PI3K and mTOR share a high degree of sequence homology. This feature has allowed the synthesis of ATP-competitive compounds targeting the catalytic site of both kinases. In preclinical models, dual PI3K/mTOR inhibitors displayed a much stronger cytotoxicity against acute leukemia cells than either PI3K inhibitors or allosteric mTOR inhibitors, such as rapamycin. At variance with rapamycin, dual PI3K/mTOR inhibitors targeted both mTOR complex 1 and mTOR complex 2, and inhibited the rapamycin-resistant phosphorylation of eukaryotic initiation factor 4E-binding protein 1, resulting in a marked inhibition of oncogenic protein translation. Therefore, they strongly reduced cell proliferation and induced an important apoptotic response. Here, we reviewed the evidence documenting that dual PI3K/mTOR inhibitors may represent a promising option for future targeted therapies of acute leukemia patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3380573PMC
http://dx.doi.org/10.18632/oncotarget.477DOI Listing
April 2012

Nuclear phosphoinositides and their roles in cell biology and disease.

Crit Rev Biochem Mol Biol 2011 Oct 14;46(5):436-57. Epub 2011 Sep 14.

Department of Human Anatomy, University of Bologna, Bologna, Italy.

Since the late 1980s, a growing body of evidence has documented that phosphoinositides and their metabolizing enzymes, which regulate a large variety of cellular functions both in the cytoplasm and at the plasma membrane, are present also within the nucleus, where they are involved in processes such as cell proliferation, differentiation, and survival. Remarkably, nuclear phosphoinositide metabolism operates independently from that present elsewhere in the cell. Although nuclear phosphoinositides generate second messengers such as diacylglycerol and inositol 1,4,5 trisphosphate, it is becoming increasingly clear that they may act by themselves to influence chromatin structure, gene expression, DNA repair, and mRNA export. The understanding of the biological roles played by phosphoinositides is supported by the recent acquisitions demonstrating the presence in the nuclear compartment of several proteins harboring phosphoinositide-binding domains. Some of these proteins have functional roles in RNA splicing/processing and chromatin assembly. Moreover, recent evidence shows that nuclear phospholipase Cβ1 (a key phosphoinositide metabolizing enzyme) could somehow be involved in the myelodysplastic syndrome, i.e. a hematopoietic disorder that frequently evolves into an acute leukemia. This review aims to highlight the most significant and updated findings about phosphoinositide metabolism in the nucleus under both physiological and pathological conditions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3109/10409238.2011.609530DOI Listing
October 2011

Inhibition of Akt signaling in hepatoma cells induces apoptotic cell death independent of Akt activation status.

Invest New Drugs 2011 Dec 14;29(6):1303-13. Epub 2010 Jul 14.

Dipartimento di Morfologia ed Embriologia, Sezione di Anatomia Umana, Signal Transduction Unit, Universita' di Ferrara, via Fossato di Mortara 66, 44100, Ferrara, Italy.

The serine/threonine kinase Akt, a downstream effector of phosphatidylinositol 3-kinase (PI3K), is involved in cell survival and anti-apoptotic signaling. Akt has been shown to be constitutively expressed in a variety of human tumors including hepatocellular carcinoma (HCC). In this report we analyzed the status of Akt pathway in three HCC cell lines, and tested cytotoxic effects of Akt pathway inhibitors LY294002, Wortmannin and Inhibitor VIII. In Mahlavu human hepatoma cells Akt was constitutively activated, as demonstrated by its Ser473 phosphorylation, downstream hyperphosphorylation of BAD on Ser136, and by a specific cell-free kinase assay. In contrast, Huh7 and HepG2 did not show hyperactivation when tested by the same criteria. Akt enzyme hyperactivation in Mahlavu was associated with a loss of PTEN protein expression. Akt signaling was inhibited by the upstream kinase inhibitors, LY294002, Wortmannin, as well as by the specific Akt Inhibitor VIII in all three hepatoma cell lines. Cytotoxicity assays with Akt inhibitors in the same cell lines indicated that they were all sensitive, but with different IC50 values as assayed by RT-CES. We also demonstrated that the cytotoxic effect was through apoptotic cell death. Our findings provide evidence for its constitutive activation in one HCC cell line, and that HCC cell lines, independent of their Akt activation status respond to Akt inhibitors by apoptotic cell death. Thus, Akt inhibition may be considered as an attractive therapeutic intervention in liver cancer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10637-010-9486-3DOI Listing
December 2011

Nuclear translocation of active AKT is required for erythroid differentiation in erythropoietin treated K562 erythroleukemia cells.

Int J Biochem Cell Biol 2009 Mar 18;41(3):570-7. Epub 2008 Jul 18.

Dipartimento di Morfologia ed Embriologia, Sezione di Anatomia Umana, Signal Transduction Unit, Universita' di Ferrara, Ferrara, Italy.

Erythroid differentiation of human erythroleukemia cell line K562 induced by erythropoietin is a complex process that involves modifications at nuclear level, including nuclear translocation of phosphatidyl-inositol 3-kinase. In this work we show that erythropoietin stimulation of K562 cells can induce nuclear translocation of active Akt, a downstream molecule of the phosphatidyl-inositol 3-kinase signaling pathway. Akt shows a peak of activity in whole cell homogenates at earlier stage when compared to the nucleus, which shows a peak delayed of 10 min. Akt increases its intranuclear amount and activity rapidly and transiently in response to EPO. Almost all Akt kinase that translocates to the nucleus shows a marked phosphorylation on serine 473. Nuclear enzyme translocation is blocked by the phosphatidyl-inositol 3-kinase inhibitor Ly294002 or Wortmannin. The specific Akt pharmacological inhibitor VI, VII and VIII that act as blocking enzyme activation inhibited translocation as well, whereas Akt inhibitor IX, that inhibits Akt activity, did not block Akt nuclear translocation. When cells were treated by means of siRNA sequences or with the Akt inhibitors the differentiation process was arrested, thus showing the requirement of the nuclear translocation of the active enzyme to differentiate. These findings strongly suggest that the intranuclear translocation of active Akt kinase represents an important step in the signaling pathway that mediates erythropoietin-induced erythroid differentiation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.biocel.2008.07.002DOI Listing
March 2009