Physical exercise is considered to be one of the beneficial factors of a proper lifestyle and is nowadays seen as an indispensable element for good health, able to lower the risk of disorders of the ...cardiovascular, endocrine and osteomuscular apparatus, immune system diseases and the onset of potential neoplasms. A moderate and programmed physical exercise has often been reported to be therapeutic both in the adulthood and in aging, since capable to promote fitness. Regular exercise alleviates the negative effects caused by free radicals and offers many health benefits, including reduced risk of all-cause mortality, sarcopenia in the skeletal muscle, chronic disease, and premature death in elderly people. However, physical performance is also known to induce oxidative stress, inflammation, and muscle fatigue. Many efforts have been carried out to identify micronutrients and natural compounds, also known as nutraceuticals, able to prevent or attenuate the exercise-induced oxidative stress and inflammation. The aim of this review is to discuss the benefits deriving from a constant physical activity and by the intake of antioxidant compounds to protect the body from oxidative stress. The attention will be focused mainly on three natural antioxidants, which are quercetin, resveratrol and curcumin. Their properties and activity will be described, as well as their benefits on physical activity and on aging, which is expected to increase through the years and can get favorable benefits from a constant exercise activity.
Highlights • We delineate the roles of mTOR in the biology of healthy and cancer cells. • We focus on the current therapeutic strategies used to inhibit mTOR. • We highlight the mechanisms of ...resistance to mTOR inhibitors. • We discuss the major challenges in the clinical use of mTOR inhibitors.
Although the prognosis of patients with localized prostate cancer is good after surgery, with a favorable response to androgen deprivation therapy, about one third of them invariably relapse, and ...progress to castration-resistant prostate cancer. Overall, prostate cancer therapies remain scarcely effective, thus it is mandatory to devise alternative treatments enhancing the efficacy of surgical castration and hormone administration.
Dysregulation of the phosphoinositide 3-kinase pathway has attracted growing attention in prostate cancer due to the highly frequent association of epigenetic and post-translational modifications as well as to genetic alterations of both phosphoinositide 3-kinase and PTEN to onset and/or progression of this malignancy, and to resistance to canonical androgen-deprivation therapy.
Here we provide a summary of the biological functions of the major players of this cascade and their deregulation in prostate cancer, summarizing the results of preclinical and clinical studies with PI3K signaling inhibitors and the reasons of failure independent from genomic changes.
•Constitutive activation of the key PI3K/AKT/mTOR molecular hub is a hallmark of cancer.•Because of frequent PTEN deletion and PIK3CA mutation, PI3K signaling is a therapeutic target in prostate cancer.•Most PI3K/AKT/mTOR inhibitors did not reach or failed phase II as monotherapy.•Major drawbacks are compensatory mechanisms and PI3K/AR transcriptional cross-regulation.•Combined AKT and AR inhibition has recently emerged as a very encouraging CRPC strategy.
The introduction of therapeutics targeting specific tumor-promoting oncogenic or non-oncogenic signaling pathways has revolutionized cancer treatment. Mechanistic (previously mammalian) target of ...rapamycin (mTOR), a highly conserved Ser/Thr kinase, is a central hub of the phosphatidylinositol 3-kinase (PI3K)/Akt/mTOR network, one of the most frequently deregulated signaling pathways in cancer, that makes it an attractive target for therapy. Numerous mTOR inhibitors have progressed to clinical trials and two of them have been officially approved as anticancer therapeutics. However, mTOR-targeting drugs have met with a very limited success in cancer patients. Frequently, the primary impediment to a successful targeted therapy in cancer is drug-resistance, either from the very beginning of the therapy (innate resistance) or after an initial response and upon repeated drug treatment (evasive or acquired resistance). Drug-resistance leads to treatment failure and relapse/progression of the disease. Resistance to mTOR inhibitors depends, among other reasons, on activation/deactivation of several signaling pathways, included those regulated by glycogen synthase kinase-3 (GSK3), a protein that targets a vast number of substrates in its repertoire, thereby orchestrating many processes that include cell proliferation and survival, metabolism, differentiation, and stemness. A detailed knowledge of the rewiring of signaling pathways triggered by exposure to mTOR inhibitors is critical to our understanding of the consequences such perturbations cause in tumors, including the emergence of drug-resistant cells.
Here, we provide the reader with an updated overview of intricate circuitries that connect mTOR and GSK3 and we relate them to the efficacy (or lack of efficacy) of mTOR inhibitors in cancer cells.
•Playing key roles in neoplastic cell pathophysiology, mTOR is an attractive target for cancer therapy.•mTOR inhibitors have met with an extremely limited success in cancer patients.•It is critical to better understand the reasons underlying the lack of efficacy of mTOR inhibition.•mTOR inhibitors cause the rewiring of several signaling pathways that dampen their efficacy.•GSK3 is emerging as a major player orchestrating resistance to mTOR-targeted therapeutics.
Acute lymphoblastic leukemia (ALL) is an aggressive hematologic neoplastic disorder that arises from the clonal expansion of transformed T-cell or B-cell precursors. Thanks to progress in ...chemotherapy protocols, ALL outcome has significantly improved. However, drug-resistance remains an unresolved issue in the treatment of ALL and toxic effects limit dose escalation of current chemotherapeutics. Therefore, the identification of novel targeted therapies to support conventional chemotherapy is required. The Wnt/β-catenin pathway is a conserved signaling axis involved in several physiological processes such as development, differentiation, and adult tissue homeostasis. As a result, deregulation of this cascade is closely related to initiation and progression of various types of cancers, including hematological malignancies. In particular, deregulation of this signaling network is involved in the transformation of healthy HSCs in leukemic stem cells (LSCs), as well as cancer cell multi-drug-resistance. This review highlights the recent findings on the role of Wnt/β-catenin in hematopoietic malignancies and provides information on the current status of Wnt/β-catenin inhibitors with respect to their therapeutic potential in the treatment of ALL.
T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive blood malignancy that arises from the clonal expansion of transformed T-cell precursors. Although T-ALL prognosis has significantly ...improved due to the development of intensive chemotherapeutic protocols, primary drug-resistant and relapsed patients still display a dismal outcome. In addition, lifelong irreversible late effects from conventional therapy are a growing problem for leukemia survivors. Therefore, novel targeted therapies are required to improve the prognosis of high-risk patients. The mechanistic target of rapamycin (mTOR) is the kinase subunit of two structurally and functionally distinct multiprotein complexes, which are referred to as mTOR complex 1 (mTORC1) and mTORC2. These two complexes regulate a variety of physiological cellular processes including protein, lipid, and nucleotide synthesis, as well as autophagy in response to external cues. However, mTOR activity is frequently deregulated in cancer, where it plays a key oncogenetic role driving tumor cell proliferation, survival, metabolic transformation, and metastatic potential. Promising preclinical studies using mTOR inhibitors have demonstrated efficacy in many human cancer types, including T-ALL. Here, we highlight our current knowledge of mTOR signaling and inhibitors in T-ALL, with an emphasis on emerging evidence of the superior efficacy of combinations consisting of mTOR inhibitors and either traditional or targeted therapeutics.
The emerging multiple roles of nuclear Akt Martelli, Alberto M.; Tabellini, Giovanna; Bressanin, Daniela ...
Biochimica et biophysica acta,
December 2012, 2012-Dec, 2012-12-00, Letnik:
1823, Številka:
12
Journal Article
Recenzirano
Odprti dostop
Akt is a central player in the signal transduction pathways activated in response to many growth factors, hormones, cytokines, and nutrients and is thought to control a myriad of cellular functions ...including proliferation and survival, autophagy, metabolism, angiogenesis, motility, and exocytosis. Moreover, dysregulated Akt activity is being implicated in the pathogenesis of a growing number of disorders, including cancer. Evidence accumulated over the past 15years has highlighted the presence of active Akt in the nucleus, where it acts as a fundamental component of key signaling pathways. For example, nuclear Akt counteracts apoptosis through a block of caspase-activated DNase: deoxyribonuclease and inhibition of chromatin condensation, and is also involved in cell cycle progression control, cell differentiation, mRNA: messenger RNA export, DNA repair, and tumorigenesis. In this review, we shall summarize the most relevant findings about nuclear Akt and its functions.
► Discussed the latest research on nuclear Akt ► Special emphasis is placed on anti-apoptotic signaling controlled by nuclear Akt. ► Nuclear Akt-interacting proteins control key processes. ► Intranuclear p-Akt levels are emerging as a predictor of tumor prognosis.
The Hedgehog (HH) signaling network is one of the main regulators of invertebrate and vertebrate embryonic development. Along with other networks, such as NOTCH and WNT, HH signaling specifies both ...the early patterning and the polarity events as well as the subsequent organ formation via the temporal and spatial regulation of cell proliferation and differentiation. However, aberrant activation of HH signaling has been identified in a broad range of malignant disorders, where it positively influences proliferation, survival, and therapeutic resistance of neoplastic cells. Inhibitors targeting the HH pathway have been tested in preclinical cancer models. The HH pathway is also overactive in other blood malignancies, including T-cell acute lymphoblastic leukemia (T-ALL). This review is intended to summarize our knowledge of the biological roles and pathophysiology of the HH pathway during normal T-cell lymphopoiesis and in T-ALL. In addition, we will discuss potential therapeutic strategies that might expand the clinical usefulness of drugs targeting the HH pathway in T-ALL.
T‐cell acute lymphoblastic leukemia (T‐ALL) is an aggressive hematological disorder that results from the clonal transformation of T‐cell precursors. Phosphatidylinositol 3‐kinase ...(PI3K)/Akt/mechanistic target of rapamycin (mTOR) and canonical Wnt/β‐catenin signaling pathways play a crucial role in T‐cell development and in self‐renewal of healthy and leukemic stem cells. Notably, β‐catenin is a transcriptional regulator of several genes involved in cancer cell proliferation and survival. In this way, aberrations of components belonging to the aforementioned networks contribute to T‐ALL pathogenesis. For this reason, inhibition of both pathways could represent an innovative strategy in this hematological malignancy. Here, we show that combined targeting of Wnt/β‐catenin pathway through ICG‐001, a CBP/β‐catenin transcription inhibitor, and of the PI3K/Akt/mTOR axis through ZSTK‐474, a PI3K inhibitor, downregulated proliferation, survival, and clonogenic activity of T‐ALL cells. ICG‐001 and ZSTK‐474 displayed cytotoxic effects, and, when combined together, induced a significant increase in apoptotic cells. This induction of apoptosis was associated with the downregulation of Wnt/β‐catenin and PI3K/Akt/mTOR pathways. All these findings were confirmed under hypoxic conditions that mimic the bone marrow niche where leukemic stem cells are believed to reside. Taken together, our findings highlight potentially promising treatment consisting of cotargeting Wnt/β‐catenin and PI3K/Akt/mTOR pathways in T‐ALL settings.
We demonstrated that cotargeting Wnt/β‐catenin (with ICG‐001) and Phosphatidylinositol 3‐kinase (PI3K)/Akt/mechanistic target of rapamycin (mTOR; with ZSTK‐474) pathways decreased proliferation, survival, and clonogenic activity of T‐cell acute lymphoblastic leukemia (T‐ALL) cells, strongly downmodulating Wnt/β‐catenin and PI3K/Akt/mTOR effectors. ICG‐001 and ZSTK‐474 had cytotoxic effects, and, when combined together, induced apoptotic cell death. All these findings were confirmed under hypoxic conditions that mimic the bone marrow niche where leukemic stem cells reside. Taken together, our findings highlight potentially promising treatment consisting of targeting Wnt/β‐catenin and PI3K/Akt/mTOR pathways in T‐ALL settings.
Glycogen synthase kinase 3 (GSK-3) is a serine/threonine (S/T) protein kinase. Although GSK-3 originally was identified to have functions in regulation of glycogen synthase, it was subsequently ...determined to have roles in multiple normal biochemical processes as well as various disease conditions. GSK-3 is sometimes referred to as a moonlighting protein due to the multiple substrates and processes which it controls. Frequently, when GSK-3 phosphorylates proteins, they are targeted for degradation. GSK-3 is often considered a component of the PI3K/PTEN/AKT/GSK-3/mTORC1 pathway as GSK-3 is frequently phosphorylated by AKT which regulates its inactivation. AKT is often active in human cancer and hence, GSK-3 is often inactivated. Moreover, GSK-3 also interacts with WNT/β-catenin signaling and β-catenin and other proteins in this pathway are targets of GSK-3. GSK-3 can modify NF-κB activity which is often expressed at high levels in cancer cells. Multiple pharmaceutical companies developed small molecule inhibitors to suppress GSK-3 activity. In addition, various natural products will modify GSK-3 activity. This review will focus on the effects of small molecule inhibitors and natural products on GSK-3 activity and provide examples where these compounds were effective in suppressing cancer growth.
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