Co-targeting of Bcl-2 and mTOR pathway triggers synergistic apoptosis in BH3 mimetics resistant acute lymphoblastic leukemia

Several chemo-resistance mechanisms including the Bcl-2 protein family overexpression and constitutive activation of the PI3K/Akt/mTOR signaling have been documented in acute lymphoblastic leukemia (ALL), encouraging targeted approaches to circumvent this clinical problem. Here we analyzed the activity of the BH3 mimetic ABT-737 in ALL, exploring the synergistic effects with the mTOR inhibitor CCI-779 on ABT-737 resistant cells. We showed that a low Mcl-1/Bcl-2 plus Bcl-xL protein ratio determined ABT-737 responsiveness. ABT-737 exposure further decreased Mcl-1, inducing apoptosis on sensitive models and primary samples, while not affecting resistant cells. Co-inhibition of Bcl-2 and the mTOR pathway resulted cytotoxic on ABT-737 resistant models, by downregulating mTORC1 activity and Mcl-1 in a proteasome-independent manner. Although Mcl-1 seemed to be critical, ectopic modulation did not correlate with apoptosis changes. Importantly, dual targeting proved effective on ABT-737 resistant samples, showing additive/synergistic effects. Together, our results show the efficacy of BH3 mimetics as single agent in the majority of the ALL samples and demonstrate that resistance to ABT-737 mostly correlated with Mcl-1 overexpression. Co-targeting of the Bcl-2 protein family and mTOR pathway enhanced drug-induced cytotoxicity by suppressing Mcl-1, providing a novel therapeutic approach to overcome BH3 mimetics resistance in ALL

Co-targeting of Bcl-2 and mTOR pathway triggers synergistic apoptosis in BH3 mimetics resistant acute lymphoblastic leukemia

: Several chemo-resistance mechanisms including the Bcl-2 protein family overexpression and constitutive activation of the PI3K/Akt/mTOR signaling have been documented in acute lymphoblastic leukemia (ALL), encouraging targeted approaches to circumvent this clinical problem. Here we analyzed the activity of the BH3 mimetic ABT-737 in ALL, exploring the synergistic effects with the mTOR inhibitor CCI-779 on ABT-737 resistant cells. We showed that a low Mcl-1/Bcl-2 plus Bcl-xL protein ratio determined ABT-737 responsiveness. ABT-737 exposure further decreased Mcl-1, inducing apoptosis on sensitive models and primary samples, while not affecting resistant cells. Co-inhibition of Bcl-2 and the mTOR pathway resulted cytotoxic on ABT-737 resistant models, by downregulating mTORC1 activity and Mcl-1 in a proteasome-independent manner. Although Mcl-1 seemed to be critical, ectopic modulation did not correlate with apoptosis changes. Importantly, dual targeting proved effective on ABT-737 resistant samples, showing additive/synergistic effects. Together, our results show the efficacy of BH3 mimetics as single agent in the majority of the ALL samples and demonstrate that resistance to ABT-737 mostly correlated with Mcl-1 overexpression. Co-targeting of the Bcl-2 protein family and mTOR pathway enhanced drug-induced cytotoxicity by suppressing Mcl-1, providing a novel therapeutic approach to overcome BH3 mimetics resistance in ALL

Co-targeting of Bcl-2 and mTOR pathway triggers synergistic apoptosis in BH3 mimetics resistant acute lymphoblastic leukemia

Several chemo-resistance mechanisms including the Bcl-2 protein family overexpression and constitutive activation of the PI3K/Akt/mTOR signaling have been documented in acute lymphoblastic leukemia (ALL), encouraging targeted approaches to circumvent this clinical problem. Here we analyzed the activity of the BH3 mimetic ABT-737 in ALL, exploring the synergistic effects with the mTOR inhibitor CCI-779 on ABT-737 resistant cells. We showed that a low Mcl-1/Bcl-2 plus Bcl-xL protein ratio determined ABT-737 responsiveness. ABT-737 exposure further decreased Mcl-1, inducing apoptosis on sensitive models and primary samples, while not affecting resistant cells. Co-inhibition of Bcl-2 and the mTOR pathway resulted cytotoxic on ABT-737 resistant models, by downregulating mTORC1 activity and Mcl-1 in a proteasome-independent manner. Although Mcl-1 seemed to be critical, ectopic modulation did not correlate with apoptosis changes. Importantly, dual targeting proved effective on ABT-737 resistant samples, showing additive/synergistic effects. Together, our results show the efficacy of BH3 mimetics as single agent in the majority of the ALL samples and demonstrate that resistance to ABT-737 mostly correlated with Mcl-1 overexpression. Co-targeting of the Bcl-2 protein family and mTOR pathway enhanced drug-induced cytotoxicity by suppressing Mcl-1, providing a novel therapeutic approach to overcome BH3 mimetics resistance in ALL

Efficacy and safety of reparixin in patients with severe covid-19 Pneumonia. A phase 3, randomized, double-blind placebo-controlled study

Introduction: Polymorphonuclear cell influx into the interstitial and bronchoalveolar spaces is a cardinal feature of severe coronavirus disease 2019 (COVID-19), principally mediated by interleukin-8 (IL-8). We sought to determine whether reparixin, a novel IL-8 pathway inhibitor, could reduce disease progression in patients hospitalized with severe COVID-19 pneumonia. Methods: In this Phase 3, randomized, double-blind, placebo-controlled, multicenter study, hospitalized adult patients with severe COVID-19 pneumonia were randomized 2:1 to receive oral reparixin 1200 mg three times daily or placebo for up to 21 days or until hospital discharge. The primary endpoint was the proportion of patients alive and free of respiratory failure at Day 28, with key secondary endpoints being the proportion of patients free of respiratory failure at Day 60, incidence of intensive care unit (ICU) admission by Day 28 and time to recovery by Day 28. Results: Of 279 patients randomized, 182 received at least one dose of reparixin and 88 received placebo. The proportion of patients alive and free of respiratory failure at Day 28 was similar in the two groups {83.5% versus 80.7%; odds ratio 1.63 [95% confidence interval (CI) 0.75, 3.51]; p = 0.216}. There were no statistically significant differences in the key secondary endpoints, but a numerically higher proportion of patients in the reparixin group were alive and free of respiratory failure at Day 60 (88.7% versus 84.6%; p = 0.195), fewer required ICU admissions by Day 28 (15.8% versus 21.7%; p = 0.168), and a higher proportion recovered by Day 28 compared with placebo (81.6% versus 74.9%; p = 0.167). Fewer patients experienced adverse events with reparixin than placebo (45.6% versus 54.5%), most mild or moderate intensity and not related to study treatment. Conclusions: This trial did not meet the primary efficacy endpoints, yet reparixin showed a trend toward limiting disease progression as an add-on therapy in COVID-19 severe pneumonia and was well tolerated. Trial registration: ClinicalTrials.gov: NCT04878055, EudraCT: 2020-005919-51

Targeting aberrant signaling pathways: novel therapeutic approaches for the treatment of acute leukemia

Over the last decades, a significant progress in the understanding of leukemogenesis has been achieved highlighting several of the molecular alterations responsible for leukemia cell proliferation and survival. Despite novel findings, advances in treatment of acute myeloid and lymphoblastic leukemia (AML, ALL) have been quite modest with the prognosis of patients remaining, generally, severe. Therefore, investigation has been prompted towards new targeted approaches focused on the aberrant networks that sustain blast proliferation, survival and drug resistance. Phosphatidyl-inositol-3 kinases (PI3Ks) belong to a family of evolutionary conserved enzymes that regulates cell omeostasis by transducing signals from the microenvironment to the nucleus through protein kinases such as Akt and the mammalian target of rapamycin (mTOR). Deregulation of the PI3K/Akt/mTOR signaling has been associated with several human cancers, and its constitutive activation is frequently found in AML patients contributing to chemoresistance, disease progression and unfavorable outcome. Over the years, several small molecules that target the PI3K/Akt/mTOR signaling has been investigated showing potential therapeutic efficacy in AML alone and in combination with chemotherapeutic drugs. Defects in apoptosis signaling which result in evasion from programmed cell death are hallmarks of cancer cells. The Bcl-2 family comprises highly conserved proteins involved in the regulation of apoptosis. Alterations in the expression levels and/or function of Bcl-2 members are widely observed in human neoplasia, including ALL, allowing cancer cells to survive irrespective of physiological or drug-induced death signals. An efficient targeting of the aberrant apoptotic machinery by BH3 mimetics has been recognized as an important strategy to improve actual ALL therapy. However, pre-existing or acquired resistance mechanisms represent a considerable challenge for the clinical use of these molecules. In this study, two novel therapeutic approaches based on target inhibition of different aberrant signaling pathways in AML and ALL have been investigated. The first study evaluates the pre-clinical activity of NVP-BKM120 (cited hereafter as BKM120), a novel selective pan-class I PI3K inhibitor, on AML cells. Previous reports have shown that BKM120 exerted cytotoxic effects in vitro and in vivo on several solid tumors and on some hematological malignancies through the selective inhibition of PI3K/Akt/mTOR activity. Conversely, a limited cytotoxicity was observed towards normal cells. Moreover, this compound synergized with well-established chemotherapeutic drugs (i.e. doxorubicin, vincristine) and novel small molecules (i.e. Mek, Bcl-2 and mTOR inhibitors). Our results demonstrate that BKM120 abrogates the activity of the PI3K/Akt/mTOR signaling at low micromolar concentrations, promoting cell growth arrest and a significant apoptosis induction in a dose- and time-dependent manner in AML cells. Conversely, no relevant cytotoxicity is observed on resting or PHA-activated normal mononuclear cells isolated from healthy volunteers. BKM120-induced cytotoxicity is associated with a profound modulation of the metabolic behavior in both cell models and primary samples, particularly reducing the oxidative capabilities and the glycolytic rates of AML cells. In addition, BKM120 synergizes with the glycolytic inhibitor dichloroacetate (DCA), triggering massive apoptosis at lower doses. Finally, in vivo administration of BKM120 to a xenotransplant mouse model of AML significantly inhibits leukemia progression and improves the overall survival of treated mice without inducing any detectble side effects. In the second study, a novel combined approach to overcome ABT-737 acquired resistance in ALL with the simultaneous inhibition of mTOR pathway by CCI-779 has been explored. It has been shown that activated PI3K/Akt/mTOR pathway decrease ABT-737 effectiveness in cancer cells by upregulating anti-apoptotic Bcl-2 family members (i.e. Mcl-1). Consistently, simultaneous inhibition strongly potentiated cytotoxicity of single agents while exerted only modest toxicity toward normal progenitors in vitro and in vivo. This strategy also triggered apoptosis under hypoxic conditions, thus indicating a potential efficacy even within tumor microenvironment. We demonstrate that co-targeting of Bcl-2 and mTOR strongly sensitized ALL cells to apoptosis, reverting the acquired ABT-737 resistance of cell models and primary samples. Analysis of signaling modulations in newly sensitized ABT-737 resistant cells reveals that ABT-737 plus CCI-779 combination reduces 4EBP1 activation and Mcl-1expression. Since the involvement of proteasomal degradation was excluded, inhibition of 4EBP1-dependent protein translation may be responsible for the synergistic interaction between ABT-737 and CCI-779. However, in some ALL models, Mcl-1 may be not the unique determinant of ABT-737 resistance since knockdown of protein expression by RNA interference does not result in significant changes of cytotoxicity. Taken together, our results (i) document that BKM120, as single agent or in combination with glycolytic modulators, has a significant anti-leukemic activity towards AML cells, thus supporting its clinical evaluation as a novel targeted agent for this hematological malignancy and (ii) identify a novel therapeutic approach to overcome ABT-737 resistance in ALL, demonstrating the synergistic interaction with the mTOR inhibitor CCI-779 and further clarify the role of Mcl-1 in mediating ABT-737 resistance

On the Verge of Institutionalisation? Participatory Budgeting Evidence in Five Italian Regions

Over the past few years, Italy has been setting the stage for different democratic innovations, especially those that have been implemented at municipal (or sub-municipal) level in different parts of the country. The expansion of Participatory Budgeting has been a remarkable one, accompanied by the diffusion of regional laws that were adopted to promote a culture of more intense civic participation. Moving from an overview of the recent diffusion of Participatory Budgeting in different areas of the country, this article proposes a reflection on what kind of added value the existence of this legal provision has led to the promotion of participation at a regional level and what this may represent. The construction of the Italian branch of Participatory Budgeting’s World Atlas offers an opportunity to assess legal provisions’ contribution to the diffusion and enrootment of participatory practices, especially in smaller-scale municipalities. Through zooming into some cases (such as Sicily, Emilia Romagna, Apulia and Tuscany, or Lazio in the last few years) the authors argue that the formalisation of participatory practices into legal frameworks today is an important but not a sufficient factor that diffuses and enroots participatory culture in local territories, and that a supplement of monitoring structures and detailed studies would help make challenges and added values of regional law frameworks clearer