The activity of a PI3K δ-sparing inhibitor, MEN1611, in non-small cell lung cancer cells with constitutive activation of the PI3K/AKT/mTOR pathway

Background

Lung cancer remains the leading cause of cancer-related death worldwide. Targeted therapies with tyrosine kinase inhibitors (TKIs) result in improvement in survival for non-small cell lung cancer (NSCLC) with activating mutations of the epidermal growth factor receptor (EGFR). Unfortunately, most patients who initially respond to EGFR-TKI ultimately develop resistance to therapy, resulting in cancer progression and relapse. Combination therapy is today a common strategy for the treatment of tumors to increase the success rate, improve the outcome and survival of patients, and avoid the selection of resistant cancer cells through the activation of compensatory pathways. In NSCLC, the phosphoinositide-3-kinase/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway has been heavily implicated in both tumorigenesis and the progression of disease.

Objectives

In this study, we investigated the efficacy of a PI3K δ-sparing inhibitor, MEN1611, in models of NSCLC sensitive and resistant to EGFR inhibitors (erlotinib and gefitinib) with a wild-type PIK3CA gene.

Methods

We performed functional, biochemical, and immunohistochemistry studies.

Results

We demonstrated good efficacy of MEN1611 in NSCLC devoid of PIK3CA gene mutations but with constitutive activation of the PI3K/AKT pathway and its synergistic effect with gefitinib both in vitro and in vivo.

Conclusions

Overall, this preclinical study indicates that the inhibitor could be a candidate for the treatment of NSCLC with an erlotinib/gefitinib-resistant phenotype and constitutive activation of the PI3K/AKT pathway, a phenotype mimicked by our model system.

Abstract 2849: The oral SERD Elacestrant in combination with the PI3K inhibitor MEN1611 inhibits tumor growth in ER+/HER2- breast cancer in vitro and in PDX models

In estrogen receptor (ER)+/HER2-breast cancer(BC), the addition of CDK4/6 inhibitors (CDK4/6i) to endocrine therapies (ET) leads to a significant increase in progression-free survival. Nevertheless, clinical resistance emerges. The upregulation of the PI3K/AKT/mTOR signaling pathway is one of the multiple acquired mechanisms of resistance to the CDK4/6i and ET combination. Thus, the extensive crosstalk between the PI3K/AKT/mTOR and ER pathways underlines the importance of targeting both pathways to overcome drug resistance in ER+/HER2- BC. Here we have evaluated the antitumor activity of Elacestrant, the oral selective estrogen receptor degrader (SERD) and antagonist, in combination with the σ-sparing PI3K inhibitor MEN1611, in vitro and in vivo in different clinically relevant BC Patient-Derived Xenograft (PDX) models, resistant to CDK4/6i and to ET, harboring mutations in PIK3CA and/or ESR1 genes. In cell-based proliferation assays, the combination of Elacestrant and MEN1611 showed a synergistic effect in inhibiting the growth of ER+ BC cell lines. In vivo data in MCF7- and patient-derived xenograft models showed compelling antitumor activity using the combination at tolerable and clinically relevant doses, compared to the single agents. In the PDX HBxC-3, wild-type for PIK3CA and ESR1 genes, the Tumor Volume-Inhibition (TVI) was 56.2%, 48.7% and 71.7% for MEN1611, Elacestrant and the combination group, respectively. In this model, the combination showed improved anti-tumor activity in comparison to the single agent treatments. In the PDX models HBxC-19 and CTG-2308, wild-type for ESR1 gene, but harboring a PIK3CA mutation, the TVI of the combination was 94.6% and 61.4%, respectively. In the latter model the combination was significantly superior to the single agents. In the PDX model CTG-1260, with PIK3CA and ESR1 mutations, MEN1611 and Elacestrant single agent treatment showed tumor growth inhibition with TVIs of 63.2% and 52.3%, while the combination showed a significant TVI of 86.9%. Overall, in all the tested in vivo models the combination of Elacestrant and MEN1611 was superior in comparison to the single agents by overcoming resistance to ER inhibition potentially driven by PI3K pathway activation in PIK3CA mutated tumors. The current data support the use of Elacestrant, the first oral SERD with positive phase III results in the EMERALD trial (Bidard et al.; JCO 2022), in combination with the PI3K inhibitor MEN1611, in ER+/HER2- mBC patients harboring PIK3CA mutations and who progressed to CDK4/6i plus ET.

Citation Format: Giuseppe Merlino, Alessio Fiascarelli, Simone Talucci, Patrizia Tunici, Mario Bigioni, Alessandro Bressan, Monica Binaschi. The oral SERD Elacestrant in combination with the PI3K inhibitor MEN1611 inhibits tumor growth in ER+/HER2- breast cancer in vitro and in PDX models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2849.

Antitumor activity of the PI3K δ-sparing inhibitor MEN1611 in PIK3CA mutated, trastuzumab-resistant HER2 + breast cancer

PURPOSE

Dysregulation of the PI3K pathway is one of the most common events in breast cancer. Here we investigate the activity of the PI3K inhibitor MEN1611 at both molecular and phenotypic levels by dissecting and comparing its profile and efficacy in HER2 + breast cancer models with other PI3K inhibitors.

METHODS

Models with different genetic backgrounds were used to investigate the pharmacological profile of MEN1611 against other PI3K inhibitors. In vitro studies evaluated cell viability, PI3K signaling, and cell death upon treatment with MEN1611. In vivo efficacy of the compound was investigated in cell line- and patient-derived xenografts models.

RESULTS

Consistent with its biochemical selectivity, MEN1611 demonstrated lower cytotoxic activity in a p110δ-driven cellular model when compared to taselisib, and higher cytotoxic activity in the p110β-driven cellular model when compared to alpelisib. Moreover, MEN1611 selectively decreased the p110α protein levels in PIK3CA mutated breast cancer cells in a concentration- and proteasome-dependent manner. In vivo, MEN1611 monotherapy showed significant and durable antitumor activity in several trastuzumab-resistant PIK3CA-mutant HER2 + PDX models. The combination of trastuzumab and MEN1611 significantly improved the efficacy compared to single agent treatment.

CONCLUSIONS

The profile of MEN1611 and its antitumoral activity suggest an improved profile as compared to pan-inhibitors, which are limited by a less than ideal safety profile, and isoform selective molecules, which may potentially promote development of resistance mechanisms. The compelling antitumor activity in combination with trastuzumab in HER2 + trastuzumab-resistant, PIK3CA mutated breast cancer models is at the basis of the ongoing B-Precise clinical trial (NCT03767335).

Abstract 1376: Dosing frequency/PD/efficacy relationship of MEN1611 in HER2 amplified, PIK3CA mutated, and refractory to Trastuzumab xenograft model of breast cancer

The PI3K-AKT-mTOR pathway is one of the most dysregulated pathways in human cancers, with PIK3CA, the gene encoding the p110α catalytic isoform of PI3K, representing the most frequently mutated gene of this network. In breast tumors, PIK3CA mutations occur in about 20% to 40% of HER2-positive and HER2-negative respectively. The lack of driver oncogenic function, hypothesized for PIK3CA mutations, paralleled by the poor clinical benefit showed by monotherapy with PI3K inhibitors in solid tumors, suggests the use of rational combinations with optimized dosing to improve PI3K inhibitor efficacy. Here we investigate the activity of the PI3K α/β selective and δ-sparing inhibitor MEN1611 in once-daily (QD) at 3.2 mg/kg versus twice-daily (BID) dosing at 1.6 mg/kg, both as a single agent and in combination with trastuzumab, to examine the correlation between drug regimen, target effect, and tumor response. The in vivo studies were investigated with the HER2 amplified, PIK3CA mutated (p.C420R), and trastuzumab-resistant JIMT-1 breast cancer cell line. To compare the effect of QD versus BID MEN1611 treatment, we evaluated the magnitude of PI3K signaling at the tumor site, by measuring the levels of pAKT and pS6 at different time points, at the beginning and the end of treatment. Anti-tumor activity was evaluated in terms of tumor volume inhibition (TVI) and by the modified response evaluation criteria in solid tumors (mRECIST). In monotherapy, although QD dosing produced a slightly longer pathway inhibition (10 vs 8 hours) than the BID, the maximum magnitude achieved was comparable. The analysis of anti-tumor efficacy, showed non-significant differences between the two schedules in terms of tumor volume inhibition (52% versus 45% for the QD and the BID respectively), confirming the PD data. In combo, BID administration was able to keep the pathway efficiently downregulated, counteracting a rebound effect observed at the 24 hour time point in the QD group of animals. Moreover, efficacy evaluation showed significant tumor-regression activity in the BID group of animals compared to the QD (79% versus 43% respectively). Although further studies are needed to evaluate time-dependent drug exposure in tumor and plasma samples, these preliminary findings support the BID clinical schedule of MEN1611 in the B-PRECISE-01 clinical trial (NCT03767335).

Citation Format: Alessio Fiascarelli, Giuseppe Merlino, Stefania Capano, Alessandro Bressan, Mario Bigioni, Andrea Pellacani, Monica Binaschi, Massimiliano Salerno. Dosing frequency/PD/efficacy relationship of MEN1611 in HER2 amplified, PIK3CA mutated, and refractory to Trastuzumab xenograft model of breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1376.

Abstract PS18-26: Men1611 promotes immune activating myeloid cell polarization

MEN1611 is a PI3K inhibitor currently in clinical development targeting the p110 α, β and γ isoforms, while sparing the δ subunit. In preclinical models, MEN1611 has demonstrated a long lasting antitumor activity when combined with trastuzumab in HER2+/PiK3CA mutated breast cancer. Aim of this work is to characterize the effects of MEN1611 on the PI3Kγ isoform, highly expressed in tumor-associated macrophages (TAMs), in order to understand whether the anti-tumor activity of MEN1611 might be also mediated by the inflammatory microenvironment. Previous evidences have shown that selective targeting of PI3Kγ by IPI-549 can reshape the inflammatory cells infiltrating tumors towards a less immunosuppressive phenotype and promote cytotoxic T cell-mediated tumor regression. In order to evaluate the effect of MEN1611 on TAMs, we established an in vitro model by differentiating murine and human macrophages from bone marrow-derived monocytes or buffy coats-isolated monocytes respectively. Pro-inflammatory M1 macrophages have been differentiated by treatment with Lipopolysaccharide (LPS) and interferon γ (IFNγ), while pro-tumoral M2 macrophages by interleukin 4 (IL-4) stimulation. The cells, thus obtained, have been incubated with MEN1611 or IPI-549 (positive control) and the effects on their phenotype, gene and protein expression, evaluated through confocal microscopy, RNASeq and flow cytometry respectively. A syngeneic xenograft model of breast cancer based on 4T1 cells has been also established in order to investigate in vivo the activity of MEN1611 on the inflammatory environment (TAMs and T cells). In vitro data showed MEN1611 and IPI-549 ability to repolarize murine and human macrophages towards a pro-inflammatory phenotype. Confocal analysis revealed a shape remodeling from an elongated M2-like towards a round M1-like; gene and protein expression analysis revealed a significant increase of immuno-stimulating factors mRNA and M1 chemokines and cytokines secretion, respectively. A modulation of the inflammatory infiltrate was also observed in vivo where RNASeq and flow cytometry analysis on dissociated treated tumors highlighted an increase of pro-inflammatory markers. The in-silico ingenuity pathway analysis (IPA) performed on genes modulated by MEN1611 revealed the enhancement of some processes related to an immune activating switch, such as the recruitment of myeloid cells or the cytotoxicity of lymphocytes and natural killer cells. In conclusion, we demonstrated in a cellular context that MEN1611 activity on PI3Kγ isoform is responsible for macrophages reprogramming from an immune-suppressive to an immune-activating phenotype. Moreover, we observed that in 4T1 murine breast cancer model, tumor regression induced by MEN1611 was also sustained by a modulation of the inflammatory microenvironment, characterized by an increased recruitment and cytotoxicity of T cells.

Citation Format: Stefania Capano, Alessandro Paoli, Alessio Fiascarelli, Andrea Massimiliano Tomirotti, Mario Bigioni, Alessandro Bressan, Daniela Bellarosa, Massimiliano Salerno, Monica Binaschi. Men1611 promotes immune activating myeloid cell polarization [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS18-26.

Targeting CD205 with the antibody drug conjugate MEN1309/OBT076 is an active new therapeutic strategy in lymphoma models

Antibody drug conjugates represent an important class of anti-cancer drugs in both solid tumors and hematological cancers. Here, we report preclinical data on the anti-tumor activity of the first-in-class antibody drug conjugate MEN1309/OBT076 targeting CD205. The study included preclinical in vitro activity screening on a large panel of cell lines, both as single agent and in combination and validation experiments on in vivo models. CD205 was first shown frequently expressed in lymphomas, leukemias and multiple myeloma by immunohistochemistry on tissue microarrays. Anti-tumor activity of MEN1309/OBT076 as single agent was then shown across 42 B-cell lymphoma cell lines with a median IC50 of 200 pM and induction of apoptosis in 25/42 (59.5%) of the cases. The activity appeared highly correlated with its target expression. After in vivo validation as the single agent, the antibody drug conjugate synergized with the BCL2 inhibitor venetoclax, and the anti-CD20 monoclonal antibody rituximab. The first-in-class antibody drug targeting CD205, MEN1309/OBT076, demonstrated strong pre-clinical anti-tumor activity in lymphoma, warranting further investigations as a single agent and in combination.

MEN1309/OBT076, a First-In-Class Antibody-Drug Conjugate Targeting CD205 in Solid Tumors

CD205 is a type I transmembrane glycoprotein and is a member of the C-type lectin receptor family. Analysis by mass spectrometry revealed that CD205 was robustly expressed and highly prevalent in a variety of solid malignancies from different histotypes. IHC confirmed the increased expression of CD205 in pancreatic, bladder, and triple-negative breast cancer (TNBC) compared with that in the corresponding normal tissues. Using immunofluorescence microscopy, rapid internalization of the CD205 antigen was observed. These results supported the development of MEN1309/OBT076, a fully humanized CD205-targeting mAb conjugated to DM4, a potent maytansinoid derivate, via a cleavable N-succinimidyl-4-(2-pyridyldithio) butanoate linker. MEN1309/OBT076 was characterized in vitro for target binding affinity, mechanism of action, and cytotoxic activity against a panel of cancer cell lines. MEN1309/OBT076 displayed selective and potent cytotoxic effects against tumor cells exhibiting strong and low to moderate CD205 expression. In vivo, MEN1309/OBT076 showed potent antitumor activity resulting in durable responses and complete tumor regressions in many TNBC, pancreatic, and bladder cancer cell line-derived and patient-derived xenograft models, independent of antigen expression levels. Finally, the pharmacokinetics and pharmacodynamic profile of MEN1309/OBT076 was characterized in pancreatic tumor-bearing mice, demonstrating that the serum level of antibody-drug conjugate (ADC) achieved through dosing was consistent with the kinetics of its antitumor activity. Overall, our data demonstrate that MEN1309/OBT076 is a novel and selective ADC with potent activity against CD205-positive tumors. These data supported the clinical development of MEN1309/OBT076, and further evaluation of this ADC is currently ongoing in the first-in-human SHUTTLE clinical trial.

Abstract 2160: MEN1611, a novel α-selective PI3K inhibitor in solid tumors

The PI3K pathway regulates various cellular processes such as proliferation, growth, apoptosis and cytoskeletal rearrangement. This pathway is frequently de-regulated and considered an oncogenic driver in human cancer. In most solid tumors, the activation of the PI3K pathway is induced by mutations of the catalytic subunit PI3Kα, present in approximately 20% to 50% of breast cancer, 14% of colorectal cancer and in 5-10% of NSCLC. Besides being an actionable target, the PI3K pathway is implicated in de novo and acquired treatment resistant in various tumor types treated with targeted therapy. As a matter of fact, the most interesting antitumor activity with PI3K inhibitors has been observed in combination. Here, we present MEN1611 (previously PA799), a PI3-kinase inhibitor with a peculiar biochemical profile targeting with high inhibition potency the mutated forms of PI3Kα and PI3Kγ. In the current study we demonstrate the anticancer activity and the pharmacodynamic effects of MEN1611 as monotherapy or in combination with targeted therapies in both xenograft and PDX models of breast cancer and in colorectal cancer and in NSCLC models, all with defined genetic profiles. MEN1611, at a clinically relevant dose, showed good antitumor activity in combination with targeted therapy agents against breast cancer, colorectal cancer and NSCLC models bearing PI3Kα mutations. A reduced activity was instead observed when the tumor models were wild type for PI3Kα or had low levels of PTEN. The antitumor activity of MEN611 was supported by its pharmacodynamic activity. In all the models, both AKT and S6 phosphorylation, markers of PI3K inhibition, were significantly inhibited upon treatment. In agreement with the biochemical profile of the drug, in PTEN null xenograft models where the tumor driver is the PI3K β-isoform, we observed lower effects in term of antitumor activity and of molecular inhibition of the pathway. Last, MEN1611 induction of hyperglycemia and insulin release was studied in the tumor models at clinical relevant dose as a marker of class-effect toxicity. MEN1611 showed significant antitumor activity in combination with other targeted therapies in breast, colon and NSCL cancer PI3Kα mutant models. Our results support the evidence that MEN611 is a PI3Kα specific inhibitor and provided the basis for the planned phase IB/II.

Citation Format: Giuseppe Merlino, Alessio Fiascarelli, Mario Bigioni, Alessandro Bressan, Clelia Irrissuto, Andrea Pellacani, Maurizio Scaltriti, Monica Binaschi. MEN1611, a novel α-selective PI3K inhibitor in solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2160.

Abstract 2145: The role of MEN1611, a class I PI3-kinases (PI3Ks) inhibitor, in reprogramming the pro-tumoral inflammatory environment

MEN1611 (previously PA799) is a specific PI3Ks inhibitor with peculiar biochemical profile: it targets at the highest potency the mutated PI3Kα isoforms and the PI3Kγ isoform. PI3Kγ isoform is abundantly expressed in myeloid cells but not in cancer cells and promotes myeloid cell trafficking during inflammation and cancer. Previous studies have shown that selective inactivation of macrophage PI3Kγ is able to promote an immunostimulatory transcriptional program that restores CD8+ T cell activation and cytotoxicity. Based on these evidences, we sought to investigate whether the anti-tumoral activity of MEN1611, that has been demonstrated especially in tumors harboring PI3Kα mutations, should be mediated also by inflammatory cells. To this aim we have set up an in vitro model in order to study macrophages polarization: in the presence of colony stimulating factor, mouse bone marrow-derived monocytes were directed into M0 macrophages differentiation, followed by M1 (by lipopolysaccharides and interferon γ) or M2 stimulation (by interleukin 4). Potential changes in macrophage phenotype induced by MEN1611 were measured by quantitative RT-qPCR and mouse cytokine antibody array. Moreover in order to evaluate in vivo the immune modulatory capacity of MEN1611 two syngeneic tumor models were established: 4T1 breast tumor model and CT26.wt colorectal tumor model. M1 or M2 polarized macrophages displayed different cell morphologies: M2 cells exhibited an higher degree of elongation compared with M1 or unstimulated M0 cells. Their activation status was tracked and confirmed by gene expression analysis, enzymatic assays (iNOS and arginase activity) and cytokine array. MEN1611 treatment was able to revert M2 cell morphology towards an M1-like round cell shape. Analysis of gene expression in MEN1611-treated macrophages showed a significant increase of immunostimulating factors mRNAs, such as IL-1b, IL-12b and iNOS, in M2 macrophages. MEN1611 also enhanced the secretion of pro-inflammatory cytokines both in M1 and M2 macrophages. In syngeneic mouse models, immune cell subsets were characterized via flow cytometry: both 4T1 and CT26.wt tumors had a similar baseline relative amount of M1 and M2 macrophages and were characterized by CD4+ and CD8+ T cells infiltrates. The impact of MEN1611 treatment on macrophages and T lymphocytes subsets infiltrating tumors is currently studied. In conclusion, we have demonstrated the ability of MEN1611 to modulate macrophage polarization towards an immune-activating phenotype at clinically relevant doses. These findings might suggest the involvement of PI3Kγ as part of MEN1611 mechanism of action.

Citation Format: Stefania Capano, Alessio Fiascarelli, Andrea M Tomirotti, Mario Bigioni, Alessandro Bressan, Daniela Bellarosa, Andrea Pellacani, Monica Binaschi. The role of MEN1611, a class I PI3-kinases (PI3Ks) inhibitor, in reprogramming the pro-tumoral inflammatory environment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2145.

Abstract 2630: MEN1309, a novel antibody drug conjugate (ADC) targeting Ly75 antigen, induces complete responses in several xenografts of solid tumors

The cell surface antigen Lymphocyte antigen 75 (LY75, CD205, DEC-205) is over-expressed in several tumor histotypes. It is a type I C-type lectin receptor (CLR), normally expressed on various APC subsets, characterized by a cytoplasmic domain containing protein motifs crucial for endocytosis and internalization upon ligation. These features make the antigen ideal to be exploited as a target for a novel ADC. MEN1309 is a humanized IgG1 antibody directed against the cell surface antigen Ly75, conjugated through a cleavable linker to a potent maytansinoid microtubule disruptor, DM4. In this study, we evaluated the in vitro and in vivo (xenografts and PDX) efficacy of MEN1309 in different tumor histotypes. A PK/PD relationship was also investigated in tumor-bearing mice. IHC demonstrated high prevalence of Ly75 in human pancreatic, triple negative breast, and bladder cancers, as well as in diffuse large B-cell lymphoma. In vitro experiments showed that cytotoxic activity of MEN1309 was in nM/sub nM range against several lymphoma, pancreatic, bladder and triple-negative breast cancer (TNBC) cell lines. Moreover, MEN1309 exhibited high cell-killing ability against cells having either strong as well as low to moderate antigen expression. In vivo, MEN1309 at 2.5-5 mg/kg (schedule varying from single dose, q7dx3, or q21dx3) showed an impressive antitumor activity, resulting in complete and long lasting responses in most of the xenograft models representing lymphoma, TNBC, bladder and pancreatic cancers, expressing the antigen at high but also at low levels. No treatment related toxicity in terms of change of body weight and death events were detected. Moreover, the administration of (i) isotype control-DM4, (ii) the non-conjugate antibody IgG1 and (iii) the free toxin DM4 (at a dosage corresponding to the equimolar concentration linked at 10 mg/kg ADC) showed little to no therapeutic efficacy on tumor growth. In TNBC patient-derived xenograft (PDX) model (coming from a heavily pre-treated patient and expressing high level of the antigen Ly75), MEN1309 (5 mg/kg q21dx3) showed a complete tumor regression. Finally, in the pancreatic adenocarcinoma xenograft model HPAFII, the pharmacokinetics profile in serum of MEN1309 at 5 mg/kg was characterized and it was qualitatively correlated, using immunofluorescence, with the occurrence of phosphorylation of Serine 10 of H3 Histone in cancer cells, as a pharmacodynamic (PD) marker of DM4 activity on microtubules. Initial ADC exposure was noteworthy and was followed by a relatively fast decline. In parallel with the decay of the serum ADC concentrations there was a progressive increase in the number of positive cells showing the PD marker for mitotic arrest. Overall, our data suggest that MEN1309 is a selective and potent novel antitumoral ADC and it deserves to enter into aPhase I study for a variety of Ly75 positive tumor histotypes.

Citation Format: Mario Bigioni, Giuseppe Merlino, Cristina Bernadó Morales, Rossana Bugianesi, Attilio Crea, Rosanna Manno, Joaquin Arribas, Rachel Dusek, Nickolas Attanasio, Keith Wilson, Christian Rohlff, Monica Binaschi. MEN1309, a novel antibody drug conjugate (ADC) targeting Ly75 antigen, induces complete responses in several xenografts of solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2630. doi:10.1158/1538-7445.AM2017-2630

CD205, a target antigen for a novel antibody drug conjugate (ADC): Evaluation of antigen expression on non-Hodgkin lymphoma (NHL)

e14039

Background: CD205 is a type I C-type lectin receptor normally expressed on various APC and some leukocyte sub-populations, characterized by a cytoplasmic domain containing protein motifs crucial for endocytosis and internalization. These features make CD205 ideal to be exploited as target of a novel ADC. MEN1309/OBT076 is a humanized IgG1 antibody against CD205, conjugated through a cleavable linker to a potent maytansinoid microtubule disruptor, DM4. Indeed, impressive results were obtained in high and low CD205 expressing xenografts for solid tumours and NHL. In vitro experimental model describing the by-stander effect of MEN1309 was implemented. Methods:A retrospective analysis to evaluate the CD205 expression on archival NHL biopsies was performed in the CRO-National Cancer Institute, Aviano IT. An immunohistochemistry (IHC) was performed on 1 slide per case, using a commercial antibody NCL-L-DEC205 (clone 11A10, Leica Biosystems). All slides were visually evaluated and a validated staining scoring system was applied, ranging from negative score 0 to strong immunostaining score 3+. Percentages (from 0 to 100%) of negative and positive tumor cells (scored as follows: 1-25% = score 1; 26-50% = score 2; 51-75% = score 3; 76-100% = score 4) were reported for each individual slide.Evaluation of correlations between CD205 expression and clinical characteristics is ongoing. Results: 100 cases of Diffuse Large B Cells Lymphomas (DLBCL) and 33 of Follicular Lymphomas (FL) were analysed. 60% of DLBCL cases were positive for CD205 and 39% had more than 25% of positive cells (score ≥2), while the 16% showed 2+/3+ staining intensity. 79% of FL cases were CD205 positive and 66% had more than 25% of positive cells, while the 27% showed 2+/3+ staining intensity. Conclusions: CD205 is heterogeneously expressed in the majority of DLBCL and FL cases. Data on the correlation between CD205 expression and clinical features will be discussed.MEN1309 has shown anti-tumour activity in vitro and in vivo even in low antigen expressing tumours. Hence CD205 expression among NHL, even if heterogeneous, makes, both DLBCL and FL, promising settings in which to explore MEN1309 activity in an upcoming FIH trial.

Proteomic screening identifies calreticulin as a miR-27a direct target repressing MHC class I cell surface exposure in colorectal cancer

Impairment of the immune response and aberrant expression of microRNAs are emerging hallmarks of tumour initiation/progression, in addition to driver gene mutations and epigenetic modifications. We performed a preliminary survey of independent adenoma and colorectal cancer (CRC) miRnoma data sets and, among the most dysregulated miRNAs, we selected miR-27a and disclosed that it is already upregulated in adenoma and further increases during the evolution to adenocarcinoma. To identify novel genes and pathways regulated by this miRNA, we employed a differential 2DE-DIGE proteome analysis. We showed that miR-27a modulates a group of proteins involved in MHC class I cell surface exposure and, mechanistically, demonstrated that calreticulin is a miR-27a direct target responsible for most downstream effects in epistasis experiments. In vitro miR-27a affected cell proliferation and angiogenesis; mouse xenografts of human CRC cell lines expressing different miR-27a levels confirmed the protein variations and recapitulated the cell growth and apoptosis effects. In vivo miR-27a inversely correlated with MHC class I molecules and calreticulin expression, CD8⁺ T cells infiltration and cytotoxic activity (LAMP-1 exposure and perforin release). Tumours with high miR-27a, low calreticulin and CD8⁺ T cells' infiltration were associated with distant metastasis and poor prognosis. Our data demonstrate that miR-27a acts as an oncomiRNA, represses MHC class I expression through calreticulin downregulation and affects tumour progression. These results may pave the way for better diagnosis, patient stratification and novel therapeutic approaches.

SAHA/Vorinostat induces the expression of the CD137 receptor/ligand system and enhances apoptosis mediated by soluble CD137 receptor in a human breast cancer cell line

HDAC inhibitors (HDACis) represent a class of anticancer agents including suberoylanilide hydroxamic acid (SAHA, Vorinostat), which has shown a strong antitumor effect, both in vitro and in vivo. Induction of apoptotic genes is an important pathway of SAHA cytotoxic mechanism of action and it has been largely described that SAHA induces sensitization of cell death receptor-resistant breast cancer cells to apoptosis. In this study, we investigated the activation of some apoptotic genes which could be responsible for the in vivo antitumor potency of SAHA in a model of human breast cancer. We found that the apoptotic gene pattern induced by SAHA in the MDA-MB-231 cell line involves the upregulation of some molecules belonging to the TNF superfamily. In particular, we demonstrated that the upregulation of the CD137 receptor/ligand system correlates with a synergistic cytotoxic effect when MDA-MB-231 cells are treated with the combination of SAHA and soluble CD137 receptor. To our knowledge, this is the first study to indicate that this member of the TNF superfamily, CD137, is modulated by SAHA treatment in breast cancer cells, suggesting that the combination of SAHA with this TNF-related receptor could be a new therapeutic approach for the treatment of tumors.

Synthesis and biological evaluation of rebeccamycin analogues modified at the imide moiety

Glycosylated indolocarbazoles related to the antibiotic rebeccamycin represent an important class of antitumour drugs. In the course of our structure-activity relationship studies, new rebeccamycin analogues modified at the imide moiety were synthesised. The antiproliferative activity of the compounds was evaluated on three human cancer cell lines, A2780 (ovarian cancer), H460 (lung cancer), and GLC4 (small-cell lung cancer). The in vitro cytotoxicity of compounds 2 and 4, characterised respectively by a 1,3-dioxolan and (1,3-dioxolan-4-yl)methylene groups linked to the imide moiety, was higher than the reference compound, edotecarin. The effect of compound 2 in inducing tumour regression in the A2780 xenograft model was also investigated.

Combined antihypertensive and cardioprotective effects of nebivolol and hydrochlorothiazide in spontaneous hypertensive rats

The antihypertensive and cardioprotective effects of the combination of nebivolol (NEB) and hydrochlorothiazide (HCTZ) in spontaneously hypertensive rats (SHR) were investigated. SHR and age-matched Wistar-Kyoto normotensive rats were randomly assigned to one of six groups: SHR treated with NEB (1 mg/kg/day, intragastric); SHR treated with HCTZ (5 mg/kg/day, intragastric); SHR treated with NEB plus HCTZ (1 + 2.5 mg/kg/day); SHR treated with NEB plus HCTZ (1 + 5 mg/kg/day), along with a SHR and a WKY control group. The effects of NEB and HCTZ on clinical chemistry parameters and on cardiac function and structure were evaluated. NEB and HCTZ in combination had synergistic antihypertensive effects and significantly reduced heart rate and blood pressure compared with monotherapy with either agent. These effects were independent of water intake, urine output and electrolyte excretion. NEB plus HCTZ was associated with reduced oxidative stress in terms of glutathione availability, lower angiotensin I levels as index of plasma renin activity and reduced clearance of urinary sodium compared with HCTZ alone. Cardiac morphometric data and antioxidant parameters indicate that NEB may influence cardiac structure by reducing hypertrophy and by enhancing the availability of endothelial nitric oxide - a unique characteristic of NEB. The authors suggest that a combination of NEB and HCTZ for the treatment of hypertension may be useful for the synergistic characteristics of both drugs.

Maintenance therapy in ovarian cancer: Molecular basis and therapeutic approach

Ovarian cancer has the highest mortality rate among gynaecological tumours despite the fact that the majority of patients with advanced disease achieve complete remission after first-line surgery and chemotherapy. Unfortunately, disease recurrence occurs in the majority of patients and second-line treatments are not curative. Clearly, the persistence of dormant and drug-resistant cells after front-line treatments results in the inability to cure the disease. The identification of cancer-initiating cells or cancer stem cells as key players in the development of recurrence has opened up a novel field of research aimed at identifying additional innovative therapeutic approaches. Strategies of maintenance therapy to extend the survival of patients have been studied, but to date no overall survival benefit has been detected. Currently, numerous clinical trials have just been completed or are ongoing involving patients achieving a complete clinical response after first-line chemotherapy in order to evaluate the efficacy of different therapeutic approaches in terms of disease-free survival and overall survival. At the 2010 ASCO meeting, the first positive results of a phase III clinical trial in this setting were presented: bevacizumab (15 mg/kg i.v. every 21 days) added to first-line chemotherapy and continued for an additional 15 cycles was found to prolong progression-free survival of 3.8 months in comparison to 6 cycles of chemotherapy alone or only 6 cycles of chemotherapy plus bevacizumab. In addition, positive results were announced for a second phase III trial testing bevacizumab in the same setting, but at half dose. The final assessment of the overall clinical benefit and the approval of bevacizumab in maintenance therapy by regulatory agencies is expected to be positive, as are the final results of abagovomab phase III trial MIMOSA, another antibody-based therapy tested as a maintenance treatment for advanced ovarian cancer patients. Encouraging preliminary results confirming the safety profile and the immunogenic activity of abagovomab were presented at the last ASCO meeting. The final results are expected to be released in the first half of 2011.

Induction of a less aggressive phenotype in human colon carcinoma HCT116 cells by chronic exposure to HDAC inhibitor SAHA

Histone deacetylase inhibitors (HDACis) are anticancer molecules that epigenetically modulate cell functions. Chronic exposure of HCT116 colon cancer cells to SAHA has been investigated for a better understanding of resistance mechanisms but, surprisingly, a less aggressive tumor phenotype both in vitro and in vivo was obtained after exposure to increasing concentrations of SAHA. Indeed, HCT116/SAHA cells when injected into nude mice showed a reduced engraftment and growth with respect to HCT116 cells. This difference was not observed inoculating the cells into NOD/SCID mice that, differently from nude mice, lack NK activity, thus suggesting the involvement of the native immune response in impairment of HCT116/SAHA cell growth. In agreement with this result, a growing induction of NKG2D ligand expression, MICA and MICB, that are molecular mediators of NK cell killing, was confirmed in HCT116/SAHA chronically exposed to SAHA. A reduced clonogenic efficiency was also observed in HCT116/SAHA with respect to HCT116 cells. Interestingly, even after chronic exposure to SAHA, HCT116/SAHA cells developed only a moderate resistance to SAHA both in vitro and in vivo and they acquired a collateral sensitivity to anthracyclines. These results are of note and probably rely on the fact that, having simultaneously many different targets, HDACis would require many different mutations to display high resistance index. Moreover, to understand the molecular basis of HCT116/SAHA cell phenotype a gene expression profile of cancer genes was evaluated in HCT116 incubated with SAHA for 24 h and in HCT116/SAHA cells to identify selectively regulated genes.

Antiproliferative and differentiating activities of a novel series of histone deacetylase inhibitors

Histone deacetylases are promising molecular targets for the development of antitumor agents. A novel series of histone deacetylase inhibitors of the hydroxamic acid type were synthesized for structure-activity studies. Thirteen tricyclic dibenzo-diazepine, -oxazepine, and -thiazepine analogues were studied and shown to induce variable degrees of histone H3/H4 and tubulin acetylation in a cellular model of myeloid leukemia sensitive to all-trans retinoic acid (ATRA). Multiparametric correlations between acetylation of the three substrates, tumor cell growth inhibition, and ATRA-dependent cytodifferentiation were performed, providing information on the chemical functionalities governing these activities. For two analogues, antitumor activity in the animal was demonstrated.

The effects of Italian Mediterranean organic diet (IMOD) on health status

OBJECTIVE

The aim of this study was to verify the effects of Italian Mediterranean Diet (IMD), consisting of organic versus conventional foods, on body composition, and biochemical parameters in a healthy individuals and in Chronic Kidney Disease (CKD) patients, in order to decrease cardiovascular diseases (CVD) risk factor and the progression of renal diseases.

DESIGN

After providing a written fully informed consent to the study, 150 Caucasian Italian men were recruited: 100 healthy male individuals (mean age 44,66+/-13,98 years; range 30-65 years) and 50 male CKD patients (mean age 46,25+/-5,97 years; range 42-54 years). These patients were affected by stage 2 and 3 of Chronic Renal Failure according to the K-DOQI 2003. Usual dietary intake and physical activity, during the previous 12 months were estimated by a semiquantitative food-frequency questionnaire. The following were measured at baseline and after consumption of conventional/organic 14 days IMD: Body mass index (BMI), Body composition, by Dual-X absorptiometry (DXA) scanner, total plasma homocysteine (tHcy), serum phosphorus, glycemia concentrations, lipid profile, and microalbuminuria.

RESULTS

A significant reduction of total homocysteine (tHcy) and phosphorus blood values were observed in the studied subjects. Body composition analysis by DXA highlighted high significant differences between conventional (T(0)) and organic diet (T(1)) for fat mass parameter, expressed as kilograms and as percentage (p<0.001). Improvement of lean body mass was observed in CDK patients (p=0.004).

CONCLUSIONS

Our study clearly demonstrates that the Italian Mediterranean Organic Diet (IMOD), according to the "Nicotera diet", was able to reduce tHcy, phosphorus, microalbuminuria levels and CVD risk in healthy individuals and in CDK patients.

Alpha-lipoic acid supplementation: a tool for obesity therapy?

Lipid peroxidation has supposed as the major biochemical alteration underling oxidant-induced cell injury in stress including numerous diseases. One of the natural molecules know to prevent or retard oxidation is alpha-lipoic acid (LA) and, therefore, the lipoic acid/dihydrolipoic acid (LA/DHLA) redox couple has received considerable attention. Recent studies have highlighted the potential of free LA and DHLA as powerful metabolic antioxidants that are able to scavenge the reactive oxygen species, to recycle other antioxidants. Our aim was to investigate the beneficial effects of LA in the treatment of Italian pre-obese and obese subjects. We screened 1612 subjects for enrollment; of these, 1127 subjects (445 men and 682 women, 18-60 age) met enrolment criteria and were enrolled in the study. According to body mass index (BMI) the 53% was obese and the 43% was pre-obese. The subjects were treated for 4 month with 800 mg/day of LA. In pre-obese subject significant reduction (p<0.001) of weight (8%, both gender), BMI (2 points), blood pressure, and abdominal circumference (female 6 cm, male 7 cm) were observed. In obese subjects significant reductions (p<0.001) of weight (9%, both gender), BMI (female 3 point, male 4 point), blood pressure and abdominal circumference (female 9 cm, male 11 cm) were observed. Our study indicated that LA is an ideal antioxidant candidate for the therapy of obesity related diseases. Further clinical studies should be considered to highlight the role and efficacy of LA treatment.

Antitumor activity of delimotecan against human metastatic melanoma: pharmacokinetics and molecular determinants

Delimotecan (MEN 4901/T-0128) is a new cytotoxic prodrug constituted by a camptothecin analog (T-2513) bound to carboxymethyl dextran through a triglycine linker. A significant antitumor activity of delimotecan against human metastatic melanoma xenograft model Me15392 is reported. Dacarbazine, the drug approved for the treatment of metastatic melanoma, was ineffective in this melanoma model. Pharmacokinetic studies, together with the expression analysis of mRNA for enzymes involved in delimotecan metabolism, showed that T-2513 and other cytotoxic metabolites of delimotecan (SN 38 and T-0055) are generated in greater quantities in the tumor tissue than in toxicity target tissues, such as liver, thus accounting for the antitumoral activity. Moreover, we demonstrated that human metastatic melanoma cells are able to phagocytose delimotecan and cleave it to release the cytotoxic moieties T-2513 in the tumoral environment. Further flow cytometric analysis showed a higher recruitment of macrophages in xenografted human metastatic melanoma, when compared with other human tumors. Thus, the antitumoral activity of delimotecan exerted on metastatic melanoma is due to several factors: (i) the ability of melanoma cells to phagocytose and metabolise delimotecan; (ii) the accumulation of delimotecan in tumoral mass; (iii) the recruitment of macrophage cells to the melanoma nodule and (iv) the expression in melanoma cells of a pattern of enzymes that converts delimotecan into cytotoxic metabolites. Based on these results, delimotecan might be exploited as a new anticancer agent for the therapy of metastatic melanoma because of its high efficacy and good selectivity, and therefore clinical trials for this indication are warranted.

Role of Interleukin-15 Receptor α Polymorphisms in Normal Weight Obese Syndrome

Previous published studies have identified a class of women, Normal Weight Obese women (NWO) with normal BMI and high fat content. An important role of Interleukin-15 (IL-15) has been documented in facilitating muscle proliferation and promoting fat depletion. Indeed the presence of three types of IL-15 receptor subunits in fat tissue suggests a direct effect on adipose tissue. We studied three single nucleotide polymorphisms (SNP) of IL-15Rα receptor gene and investigated their relationship with NWO phenotype. We considered two classes of women according to their BMI and percent fat mass (%FAT), class 1: including 72 overweight-obese women (high BMI-high fat mass) and class 2: including 36 NWO (normal BMI, high fat mass). Three sites of Interleukin-15 receptor subunit α gene were examined, located respectively in exon4, exon5 intron-exon border and exon7. Genotyping of the identified polymorphisms was performed by restriction fragment length polymorphism. Haplotype frequency estimation was performed by using the Mendel-University of Chicago program. Odds ratio analyses were calculated by EPISTAT program. Highly significant differences were observed for exon 7-exon5 intron-exon border and exon 4-exon 7 haplotype distribution between class 1 and class 2 women. These results strongly support the hypothesis that genetic variability of the IL-15 receptor has an important role in body fat composition. Our data underscore previous findings that suggest a potential role of IL-15 cytokine in NWO syndrome.

Antitumour effect of combination treatment with Sabarubicin (MEN 10755) and cis-platin (DDP) in human lung tumour xenograft

PURPOSE

Sabarubicin (MEN 10755), a new disaccaride anthracycline, has shown greater efficacy than Doxorubicin in a large panel of preclinical models and now it is in phase II clinical trials. Its promising antitumour activity promoted considerable interest to combine Sabarubicin with other antitumour agents. Thus, the purpose of this study was to evaluate in vitro cytotoxic effects and in vivo antitumour activities produced by the combination of Sabarubicin and cisplatin (DDP).

METHODS

The antitumour effect of Sabarubicin and DDP association was investigated, in vitro and in vivo, in preclinical models of lung cancer i.e.: the non-small cell lung carcinoma (NSCLC) H460 and the small-cell lung carcinoma (SCLC) GLC4 in terms of synergism, additivity or antagonism in order to establish the best schedule for the combined treatment. Further, the correlation between antitumour activity and the pharmacokinetic parameters of the studied combination was also evaluated.

RESULTS

The drug combination in vitro was in general more cytotoxic than the single drug alone, indicating the presence of a synergistic effect in both tumour cell lines. Also, in the xenograft experiments a superior antitumoral effect was observed when Sabarubicin was combined with DDP. The antitumour efficacy of Sabarubicin (6 mg/kg q4d x 5) combined with DDP (6 mg/kg q4d x 3) greatly depended on the schedule of administration. In H460 tumour line, the sequential combination was more effective than the simultaneous administration of the two agents, although the antitumour efficacy was not dependent on the sequence of combination. On the other hand, a strong sequence-dependent effect was observed when Sabarubicin was combined with DDP in SCLC, GLC4. In particular, the highest value of LCK = 6.7 was obtained when administration of DDP followed by 24 h that of Sabarubicin. Pharmacokinetics of Sabarubicin in combination with DDP was evaluated at 6 mg/kg for both drugs with different sequential schedule. The experimental data showed no evidence for pharmacokinetics drug-drug interaction.

CONCLUSION

These preclinical results indicate the potential for a strong antitumour activity in lung tumours of the combination Sabarubicin and DDP. In particular, in SCLC the best response should be given by a sequence with administration of Sabarubicin followed 24 h later by that of DDP. Clinical trials based on these results are ongoing.

Sabarubicin (MEN10755)-induced apoptosis is independent from mtDNA in A2780 human ovarian tumor cells

BACKGROUND

The role of mitochondrial DNA (mtDNA) in anthracycline-induced apoptosis is controversial. Sabarubicin accumulates in the mitochondria of A2780 human ovarian tumor cells. The effects of this new anthracycline on the structure and the functionality of mtDNA, as well as on the apoptosis of mtDNA-depleted cells have been investigated.

MATERIALS AND METHODS

Sabarubicin-induced mtDNA cleavage was detected by Southern blotting and mitochondrial mRNA expression was analyzed by real-time PCR. Apoptosis was studied in mtDNA-depleted (theta0) and parental (theta+) A2780 cells detecting nuclear DNA fragmentation using ELISA and cytofluorimetrically using Annexin V/PI staining. Mitochondrial membrane potential was studied using the cyanine dye JC-1.

RESULTS

Sabarubicin induced mtDNA cleavage in the A2780 cells, but this damage did not affect mitochondrial mRNA expression. Apoptosis was induced by sabarubicin in theta0 as well as in theta+ cells.

CONCLUSION

The results showed that mtDNA did not influence anthracycline-induced apoptosis in A2780 cells.

Is antioxidant plasma status in humans a consequence of the antioxidant food content influence?

BACKGROUND

A constantly growing part of consumers considers the organic foods healthier than the conventional foods. However, so far few nutritional intervention studies in humans are available on the comparison of organic and conventional food products.

OBJECTIVE

The aim of the present work was to compare the total antioxidant activity of organic versus conventional fruits (apples, pears, red oranges, lemons, strawberries and bananas), vegetables (lettuces, tomatoes, onions, garlics, carrots, beans, potatoes, celeries, peas, courgettes and zucchinies), red wine and milk.

DESIGN

The oxygen radical absorbing capacity (ORAC) procedure was used to determine both the antioxidant activity of food from organic or conventional origin, and the human plasma antioxidant capacity. Ten Caucasian Italian men, aged 30-65 years, were recruited. The subjects were healthy, according to the clinical examination and the disease history, none smoked or took any drug. Anthropometric parameters of all the participants were measured.

RESULTS

The ORAC values of most part of organic foods, i.e. fruits, vegetables as well as red wine and milk were significantly (p < 0.005) higher than those of the conventional homologues. Three organic foods, i.e. pears (-25%) (p < 0.01), lettuces (-20%) (p < 0.01), and tomatoes salsas (-4%) showed ORAC values lower than the conventional homologues. After the consumption of 14 days Mediterranean organic diet a significant (p < 0.005) increase (21%) of the human plasma total antioxidant capacity was observed.

CONCLUSIONS

Our results clearly show that the organic food products have an higher total antioxidant activity and bioactivity than the conventional foods. The results could be used in public health campaign to increase the consumption of products able to provide a significant health protection and prevention of chronic diseases.

Human and murine macrophages mediate activation of MEN 4901/T-0128: a new promising camptothecin analogue-polysaccharide conjugate

MEN 4901/T-0128 is a new cytotoxic prodrug constituted by the camptothecin analogue T-2513 bound to carboxymethyl dextran through a triglycine linker. MEN 4901/T-0128 was designed to target the active camptothecin at the tumour site. MEN 4901/T-0128 is weakly cytotoxic in vitro and thus T-2513 must be released from the conjugate to become active. Here, we demonstrated that human purified cathepsin B releases T-2513 from MEN 4901/T-0128 at pH values ranging from 3 to 5. pH dependency of this reaction suggests that cleavage of the linker should mainly occur in the lysosomes. As elevated cathepsin B activity has been described in macrophages, human tumour monocytic THP-1 cells differentiated into macrophage-like cells were used to study the cellular mechanisms responsible for MEN 4901/T-0128 antitumour activity. Here, we show that differentiated THP-1 internalizes MEN 4901/T-0128 efficiently in a time-dependent and concentration-dependent manner. After phagocytosis, THP-1 cells can cleave the prodrug and release T-2513 in the media. On the contrary, undifferentiated THP-1 cells or pancreatic ASPC-1 tumour cells, although expressing high levels of cathepsin B, are much less efficient in the release of cytotoxic moieties in the culture media. Moreover, normal murine macrophages, recovered from the peritoneal cavity or from the spleen, when activated (in vitro by 100 ng/ml phorbol 12-myristate-13-acetate and in vivo by 300 microl of 3% w/v thioglycollate solution), were able to release (after incubation with 10 microg/ml MEN 4901/T-0128) cytotoxic moieties in the culture supernatant, in an amount sufficient to kill human carcinoma A2780 cells. Thus, we suggest that tumour-associated macrophages may play a key role in the uptake of MEN 4901/T-0128, cleavage and local release of active moiety T-2513. This mechanism should support a tumour targeting of the cytotoxic moieties, allowing an improved antitumour efficacy/safety ratio for MEN 4901/T-0128.

Normal-weight obese syndrome: early inflammation?

BACKGROUND

In obese subjects, the adipose mass represents an important source of proinflammatory cytokines. We have identified a new syndrome-the normal-weight obese (NWO) syndrome-in women with normal weight and body mass index but whose fat mass is >30% of their total body weight and whose risk of developing obesity-related diseases is likely increased.

OBJECTIVE

The aim of the present study was to verify the hypothesis that NWO women are characterized by early inflammation, related to body fat mass, and that their plasma proinflammatory cytokine concentrations are greater than those of nonobese women.

DESIGN

Twenty NWO, 20 preobese-obese, and 20 healthy (nonobese), age-matched white Italian women were studied. Anthropometric variables and plasma concentrations of proinflammatory cytokines and cardiovascular disease (CVD) risk factors were measured and compared between groups.

RESULTS

Plasma values and body-composition measures were significantly different between the preobese-obese and nonobese women. No significant differences in body weight, laboratory values, or CVD risk factors were found between the NWO and nonobese groups. Compared with concentrations in the NWO women, plasma concentrations of interleukin (IL)-1alpha, IL-1beta, IL-6, IL-8, and TNF-alpha were significantly lower in the nonobese group and were significantly greater in the preobese-obese group. IL-6 and TNF-alpha concentrations were related to fat mass distribution in the NWO women.

CONCLUSIONS

The proinflammatory cytokines could be regarded as significant prognostic indicators of the risk of obesity, CVD, and the metabolic syndrome in NWO women.

Interleukin-1 (IL-1) receptor antagonist gene polymorphism in normal weight obese syndrome: relationship to body composition and IL-1 alpha and beta plasma levels

Interleukin-1 receptor antagonist concentration is upregulated in the plasma of patients with obese related disease, and its synthesis is under genetic control. We tested the hypothesis that the polymorphism in the interleukin-1 receptor antagonist gene second intron might be associated with normal weight obese syndrome. The polymorphism of intron 2 in the interleukin-1 receptor antagonist gene, containing a variable numbers of a tandem repeat (VNTR), and interleukin-1alpha and beta plasma levels were evaluated in 110 Caucasian Italian women, divided in three groups: non-obese, normal weight obese and preobese-obese. The allele 1 frequency was not significantly different in the three groups. The alleles 3 and 4 were not observed in any group. The allele 2 frequency in normal weight obese woman (12.5%) and preobese-obese (17.5%) groups were significantly different in comparison with the non-obese group (6.7%). The allele 5 was observed exclusively in non-obese and normal weight obese subjects (13.3 and 7.5%, respectively). In normal weight obese women, plasma concentrations of interleukin-1 alpha and interleukin-1 beta were significantly higher than in non-obese. The allele 2 was observed in normal weight obese as well as a significant association between the increase of interleukin-1 beta plasma amount and the allele 2 carrier. Our findings suggest that the allele 2 might be an important high-risk genetic marker for normal weight obese syndrome and obesity related diseases.

Normal Weight Obese syndrome: role of single nucleotide polymorphism of IL-1 5Ralpha and MTHFR 677C-->T genes in the relationship between body composition and resting metabolic rate

We have identified a subset of metabolically obese, but normal weight individuals, with potentially increased risks of developing the metabolic syndrome, despite their normal body mass index. We determined the relationship among body fat distribution, resting metabolic rate (RMR), total body water amount (%TBW), selected gene polymorphism on interleukin-15 receptor-alpha (IL-15Ralpha) and methylenetetrahydrofolate reductase 677C-->T (MTHFR 677C-->T), to distinguish normal weight obese (NWO) from nonobese with a normal metabolic profile and obese individuals. We analysed anthropometric variables, body composition by Dual energy X-ray Absorptiometry (DXA), RMR by indirect calorimetry, %TBW by bioimpedence analysis (BIA), MTHFR 677C-->T and IL-15Ralpha genotypes of 128 clinically healthy Caucasian individuals. We compared a group of female, defined as NWO and characterised by a BMI < or = 25 kg/m(2) and FM > or = 30% with groups of others female, and males, represented by nonobese with a BMI < or = 25 kg/m(2) and FM < or = 30%, and preobese-obese individuals with BMI > or = 25 kg/m(2) and %FM > or = 30%; none of the males was classified as NWO. Significant correlations were found among body fat mass distribution, metabolic variables, percentage of total body water distribution and selected genetic variations. The variables that contributed significantly to the separation of classes were body tissue (Tissue), %TBW, RMR, the volumes of both oxygen (VO2) and carbon dioxide (VCO2). The distribution of MTHFR 677C-->T and IL-15 genotypes was significantly different between classes. Our data highlight that NWO individuals showed a significant relationship between the decrease in the basal metabolism (RMR), body fat mass increasing and total water amount. Possession of wild type homozygotes genotypes regarding IL-15Ralpha cytokine and 677C-->T MTHFR enzyme characterised NWO individuals.

Body composition analyses in normal weight obese women

The purpose of this study was to identify new indexes of body composition that characterize the normal weight obese (NWO) women. We measured body composition by dual energy x-ray absorptiometry (DXA) and resting metabolic rate (RMR) by indirect calorimetry in a cohort of seventy-five healthy Italian women, subdivided into three groups (nonobese/controls, NWO, preobese-obese women). Despite a normal body mass index (BMI), the NWO women have a higher body fat mass percentage (FAT %) (38.99 +/- 6.03) associated to a significant (p = 0.02) lower amount of lean mass of legs (12.24 +/- 1.31) and lean mass of left leg (6.07 +/- 0.64) with respect to the control group. The NWO group showed a significant (p = 0.043) lower RMR (1201.25 +/- 349.02) in comparison with nonobese and preobese-obese women. To classify NWO individuals among general population, we identified three significant body composition indexes: abdominal index, leg index and trunk index. The NWO women showed significant increased value in the three indexes (p < 0.001). Our results suggest that, despite a normal BMI, the NWO women displayed a cluster of anthropometric characteristics (body fat mass percentage, leg indexes) not different to obese women ones. An appropriate diet-therapy and physical activity may be protecting NWO individuals from diabetes and cardiovascular diseases associated to preobese-obese women.

Role of NK-1 and NK-2 tachykinin receptor antagonism on the growth of human breast carcinoma cell line MDA-MB-231

We demonstrate that neurokinin A (NKA) and substance P (SP) play a role in the proliferation of the estrogen receptor-negative (ER-) cell line MDA-MB-231, a human breast carcinoma expressing both NK-1 and NK-2 receptors. In vitro experiments showed that the specific receptor antagonists MEN 11,467 (NK-1) and nepadutant (MEN 11,420; NK-2) inhibited tumor cell proliferation, and blocked the stimulatory effect of SP and NKA. Anti-tumoral activity of NK-1 and NK-2 receptor antagonists was demonstrated in nude mice, measuring growth inhibition of MDA-MB-231 tumor cells xenografted s.c. and by using the hollow-fiber assay. In both systems a significant inhibition was found when compounds were administered at 5 mg/kg i.v. every day for 2 weeks. Results obtained from both these models suggest that the in vivo activity of NK-1 and NK-2 antagonists may be a result of a cytostatic effect rather than a cytotoxic effect. Our results suggest that the control of breast carcinoma (ER-) growth by tachykinin receptor antagonists may become a new form of targeted therapy for these human tumors.

Involvement of nitric oxide in both central and peripheral haemodynamic effect of d/l-nebivolol and its enantiomers in rats

The cardiovascular profile of the racemate D/L-nebivolol and its enantiomers administered by intravenous (i.v.) or by intracerebroventricular (i.c.v.) route was investigated in anaesthetized normotensive rats. D/L-Nebivolol (0.1-0.5 mg/kg) induced a dose-related reduction in blood pressure when administered by i.c.v. route. These hypotensive effects were more marked as compared to those achieved by peripheral administration of D/L-nebivolol (0.1-1 mg/kg i.v.). Both enantiomers contributed to the hypotensive effect of D/L-nebivolol by i.c.v. route, while the effects of the drug on blood pressure by i.v. route were due to the d-enantiomer. The bradycardic effect of the racemic form given i.v. was dose-related and, at the highest dose (1 mg/kg), was more pronounced as compared to i.c.v. route. D-Nebivolol was responsible for chronotropic effects by both the i.v. and i.c.v. route, although by i.c.v. route L-nebivolol also induced a reduction in heart rate. The nitric oxide synthase inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) administered at 5 mg/kg i.v. bolus + 0.1 mg/kg/min infusion or at 2.5 mg/kg i.c.v. counteracted the effects of D/L-nebivolol (either 1 mg/kg i.v. or 0.5 mg/kg i.c.v.) on blood pressure, while it did not inhibit the cardiovascular changes induced by isoprenaline (300 ng/kg i.v.) or calcitonin gene-related peptide (CGRP; 400 ng/kg i.v.). In addition, i.c.v. effects of D/L-nebivolol on blood pressure and heart rate were not affected by pre-treatment with atropine (2 mg/kg i.v.). The present findings demonstrate that D/L-nebivolol produced haemodynamic changes following both peripheral and central administration; these latter findings are mainly due to its L-enantiomer and these effects involve the L-arginine/nitric oxide pathway.

MEN15658: a new promising anti-tumoral drug active on resistant tumor cells

We describe the identification of MEN15658, a molecule characterized by a promising cytotoxic effect against human tumor cell lines, including platinum- and anthracycline-resistant ovarian carcinoma. MEN15658 induces p53 accumulation, and activation of gadd-45, p21, c-fos and bcl-2 family genes in human ovarian carcinoma A2780 cell line. The compound causes a block in S phase of the cell cycle, inducing apoptotic cell death, thus suggesting an involvement of DNA damage in the MEN15658 effect on tumor cells. The anti-tumoral activity observed against the human ovarian carcinoma A2780 cell line xenotransplanted in nude mice makes this compound a new promising anti-tumoral drug.

Pharmacological profile of MEN 11066, a novel potent and selective aromatase inhibitor

MEN 11066 is a new non-steroidal compound which potently inhibits human placenta (K(i)=0.5 nM) and rat ovarian (K(i)=0.2 nM) aromatase in vitro. In vivo, a single oral dose of 0.3 mgkg(-1) significantly decreased uterus weight in immature rats after stimulation of uterus growth by androstenedione. MEN 11066 reduced in a dose-dependent manner plasma estradiol levels in adult female rats treated with pregnant mare serum gonadotropin (PMSG). After 2 weeks of repeated daily treatment in adult rats, a significant decrease in uterine weight was observed together with a 65% decrease in plasma estradiol, whereas plasma levels of testosterone, progesterone, aldosterone, corticosterone, cholesterol, LH and FSH were not affected. The lack of any effect by MEN 11066 on adrenal steroids was confirmed by the unchanged plasma corticosterone and aldosterone levels in immature rats and also in adult rats when the repeated treatment with MEN 11066 (15 days) was followed by the administration of a synthetic ACTH analogue. No change in 11beta-hydroxylase or 21-hydroxylase activities was produced in vitro by the addition of 10 microM MEN 11066. Fifteen-day treatment with MEN 11066 did not produce changes in several rat hepatic enzymatic activities involved in the metabolism of xenobiotics. These results demonstrated that MEN 11066 is a potent inhibitor of aromatase which does not interfere with the cytochrome P450 involved in the synthesis of other steroids or in the metabolism of xenobiotics.

CD137 and CD137 ligand constitutively coexpressed on human T and B leukemia cells signal proliferation and survival

CD137, a member of the tumor necrosis factor receptor family, provides expansion and survival signal to T cells. Its ligand, CD137L, in addition to its ability to costimulate T cells, signals back into antigen presenting cells promoting their activation and differentiation. Recently, CD137 has been proposed as a therapeutic target to improve and sustain anticancer immune response. Several activated T leukemia and B lymphoma cell lines expressed CD137 or CD137L, respectively, and soluble CD137L has been found in sera of leukemia patients. However, the functionality and role of these costimulatory molecules in hematologic malignancies are until now unknown. Interestingly, we observed constitutive CD137 and CD137L coexpression on both human T and B leukemia cell lines. The constitutive CD137 expression on unstimulated T or B leukemia cells presents some differences compared to CD137 expressed on PMA/ionomycin-activated T leukemia cells. Surprisingly, in spite of the low expression level, both tumor CD137 and CD137L molecules signaled in T and B leukemia cells inducing proliferation and prolonging survival. In addition, CD137/CD137L system ligation opposed the anticancer drug cytotoxic effects, reducing the apoptotic DNA fragmentation and stimulating proliferation of doxorubicin-escaped leukemia cells. Although the role of leukemia CD137/CD137L system in vivo is unknown, these data suggest that these costimulatory molecules might confer an advantage to hematologic tumors promoting survival, sustaining cellular growth and contributing to drug resistance.

Novel anthracycline oligosaccharides: influence of chemical modifications of the carbohydrate moiety on biological activity

Several observations highlight the importance of the carbohydrate moiety for the biological activity of antitumoural anthracyclines. Here is reported the synthesis, cytotoxicity and topoisomerase II-mediated DNA cleavage intensity of the new oligosaccharide anthracyclines 1--4 modified in the sugar residue. Evaluation of cytotoxic potency on different cell lines, resulted in quite similar values among the different analogues. On the other hand, topoisomerase II-mediated DNA breaks level was different for the various compounds, and was not related to cytotoxicity, thus supporting previous observations reported for some monosaccharide anthracyclines modified in the carbohydrate portion.

Anthracyclines: selected new developments

Anthracycline antibiotics play an important role in cancer chemotherapy. The need for an improvement of their therapeutic index has stimulated an ongoing search for anthracycline analogues with improved properties. Analogue development was originally limited by a lack of information on the cellular drug target, nevertheless almost 20 years ago the mechanism of action of doxorubicin and daunorubicin was revealed and DNA topoisomerase II was recognised to be their main cellular target. Several anthracyclines interfere with topoisomerase II functions by stabilizing a reaction intermediate in which DNA strands are cut and covalently linked to tyrosine residues of the enzyme. Investigations on the sequence specificity of doxorubicin in vitro and in nuclear chromatin of living cell have led to a molecular model of drug receptor on the topoisomerase II-DNA complex. Anthracyclines are likely placed at the interface between the DNA cleavage site and the active site of the enzyme, forming a DNA-drug-enzyme ternary complex. Moreover, a quite detailed structure-function relationship has been established for anthracyclines. First, drug intercalation is necessary but not sufficient for topoisomerase II poisoning; second, the removal of the 4-methoxy and 3'-amino substituents greatly increases the drug activity and third, the 3' substituent of the sugar moiety markedly influences the sequence selectivity of anthracycline-stimulated DNA cleavage. These relationships have been exploited during the last decade by several groups, including ours, in the search for new anthracycline drugs with lower side effects and higher activity against resistant cancer cells. This review will focus on areas of the anthracycline field including synthesis of new analogues, new strategies of synthesis and recent developments in the area of drug delivery.

A comparative study of cellular and molecular pharmacology of doxorubicin and MEN 10755, a disaccharide analogue11Abbreviations: DOX, doxorubicin; DNA-SSB, single-strand breaks; and DNA-DSB, double-strand breaks

MEN 10755 is a disaccharide anthracycline endowed with a broader spectrum of antitumour activity than doxorubicin (DOX). To investigate the cellular and molecular basis of its action, cytotoxic activity, drug uptake, subcellular localisation, induction of DNA damage, and apoptosis were assessed in the human A2780 ovarian carcinoma cell line. Experiments with radiolabelled anthracyclines indicated that MEN 10755 exhibited reduced cellular accumulation and a different subcellular distribution (higher cytoplasmic/nuclear ratio) than DOX. In spite of the lower nuclear concentration, MEN 10755 was as potent as DOX in eliciting DNA single- and double-strand breaks, G2/M cell arrest, and apoptosis. Sequencing of drug-induced topoisomerase II cleavage sites showed a common DNA cleavage pattern for MEN 10755 and DOX. Cleavage sites were always characterised by the presence of adenine in -1 position. However, the extent of DNA cleavage stimulation induced by MEN 10755 was greater than that produced by DOX. Reversibility studies showed that MEN 10755-stimulated DNA cleavage sites were more persistent than those induced by DOX, thus suggesting a more stable interaction of the drug in the ternary complex. As a whole, the study indicated that the cellular pharmacokinetics of MEN 10755 substantially differs from that of DOX, showing a lower uptake and a different subcellular disposition. In spite of the apparently unfavourable cellular pharmacokinetics, MEN 10755 was still as potent as DOX in inducing topoisomerase-mediated DNA damage. Although the extent and persistence of protein-associated DNA breaks may contribute to the cytotoxic effects, the drug's efficacy as apoptosis inducer and antitumour agent could not be adequately explained on the basis of DNA damage mediated by the known target (i.e. topoisomerase II), thus supporting additional cellular effects that may be relevant in cellular response.

Cardioprotective effects of zofenopril, a new angiotensin-converting enzyme inhibitor, on doxorubicin-induced cardiotoxicity in the rat

We have studied the effect of zofenopril, a new angiotensin-converting enzyme inhibitor in preventing cardiac injury induced by chronic doxorubicin treatment in rats. Cardiac function was assessed by measuring changes in electrocardiogram (ECG) tracings, haemodynamics and cardiac responses in vivo to isoprenaline, 4 weeks after suspension of doxorubicin treatment, in vehicle-treated rats and in animals receiving zofenopril (15 mg/kg/os/day) alone, doxorubicin (1.5 mg/kg i.v. once a week for 5 weeks) or zofenopril+doxorubicin treatment. Doxorubicin induced a significant lengthening of the QalphaT interval, which was completely prevented by zofenopril treatment. The cardiac positive inotropic effect induced by i.v. isoprenaline was selectively depressed by doxorubicin (no changes in chronotropic responses) and this adverse effect of doxorubicin was also prevented in zofenopril+doxorubicin pretreated rats. Doxorubicin induced a significant increase in relative heart weight, which was likewise prevented in zofenopril+doxorubicin treated rats. In separate experiments, zofenopril did not interfere with the antitumor activity of doxorubicin (inhibition of tumor growth in nude mice xenografted with A2780 human tumor line). In conclusion, the oral administration of zofenopril is able to significantly ameliorate, up to 4 weeks after the end of doxorubicin administration, doxorubicin-induced cardiotoxicity without affecting the antitumor activity of this anthracycline.