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PDF file, 58KB, Distribution of clinico-pathological characteristics in the clinical cohort II.

PDF file, 39KB, IC50 of the used panel of cell lines.

PDF file, 67KB, Line chart showing the gene expression values for the cell lines at the baseline and upon serum starvation. On the left and right male and female cell lines are represented, respectively. On the top and bottom results for TUBB3 and TUBB6 are shown, respectively. All the results were normalised having as 1 the expression values of the A2780 cell line. The results are the average of three independent experiments. Expression values are shown in a log scale to take into account the difference in the expression between the different cell lines.

Purpose: Colorectal cancer is one of the deadliest diseases in Western countries. To predict the outcome of therapy, we assessed the role of class III (TUBB3) and class V β-tubulin (TUBB6) as predictive biomarkers.Experimental Design: Using immunohistochemistry and nanofluidics, the expression of TUBB3 and TUBB6 was assessed in two cohorts of 180 and 134 patients, respectively. The CYP17A1 RS743572 was genotyped to identify GG carriers with enhanced androgen levels. TUBB3 and TUBB6 were investigated in 22 colorectal cancer cell lines in basal conditions and after serum starvation, the latter serving as activator of this prosurvival pathway. To ascertain the role of androgen receptor (AR) in such regulation, we silenced AR and checked TUBB3 and TUBB6 expression and sensitivity to chemotherapy.Results: There was a link between poor survival, the expression of TUBB3/TUBB6, and AR only in females. Conversely, only in males carriers of the GG phenotype exhibited the worst outcome. Importantly, male cell lines were resistant to serum starvation and exhibited higher levels of TUBB6, thereby suggesting that the pathway is activated by androgens. In female cells this phenomenon was absent. In both genders, AR was the main driver of TUBB3/TUBB6 expression, as constitutive silencing of AR was associated with downregulation of TUBB3/TUBB6 expression and increased sensitivity to oxaliplatin and SN-38.Conclusions: The involvement of androgens in the TUBB3 pathway opens the way for clinical trials to assess the efficacy of antiandrogens for increasing the efficacy of chemotherapy in male colorectal cancer patients. Clin Cancer Res; 18(10); 2964–75. ©2012 AACR.

PDF file, 50KB, Distribution of clinico-pathological characteristics in the clinical cohort I.

Supplementary Fig from Proteomic characterization of cytoskeletal and mitochondrial class III β-tubulin

PDF file, 64KB, Gene expression data for TUBB3, TUBB6, AR and AR-V7 for the panel of cell lines used in this study.

PDF file, 976KB, Representative Immunhistochemistry for TUBB6 PDF (956KB) Source File (PPTX) 2960KB At the top representative immunohistochemistry of a section of normal colon. Normal colonic cells are TUBB6 negative. At the bottom a section coming from a colorectal cancer with 1005 of TUBB6 staining.

PDF file, 15KB, Bar chart showing gene expression of TUBB3 and TUBB6 in colorectal cancer cells cultured in the presence of R1881. Bar and error bars represent mean and SD of two independent experiments. Control cellswere equal to 1 and treated only with the vehicle ethanol 1%.

Class III β-tubulin (TUBB3) has been discovered as a marker of drug resistance in human cancer. To get insights into the mechanisms by which this protein is involved in drug resistance, we analyzed TUBB3 in a panel of drug-sensitive and drug-resistant cell lines. We identified two main different isoforms of TUBB3 having a specific electrophoretic profile. We showed that the apparently higher molecular weight isoform is glycosylated and phosphorylated and it is localized in the cytoskeleton. The apparently lower molecular weight isoform is instead found exclusively in mitochondria. We observed that levels of phosphorylation and glycosylation of TUBB3 are associated with the resistant phenotype and compartmentalization into cytoskeleton. By two-dimensional nonreduced/reduced SDS-PAGE analysis, we also found that TUBB3 protein in vivo forms protein complexes through intermolecular disulfide bridges. Through TUBB3 immunoprecipitation, we isolated protein species able to interact with TUBB3. Following trypsin digestion, these proteins were characterized by mass spectrometry analysis. Functional analysis revealed that these proteins are involved in adaptation to oxidative stress and glucose deprivation, thereby suggesting that TUBB3 is a survival factor able to directly contribute to drug resistance. Moreover, glycosylation of TUBB3 could represent an attractive pathway whose inhibition could hamper cytoskeletal compartmentalization and TUBB3 function. [Mol Cancer Ther 2008;7(7):2070–9]

Supplementary Table S1 from Proteomic characterization of cytoskeletal and mitochondrial class III β-tubulin

Supplementary Tables 1-3 from Paclitaxel Directly Binds to Bcl-2 and Functionally Mimics Activity of Nur77

The supply of oxygen and nutrients to solid tumors is inefficient because cancer tissues have an inadequate number of microvessels, thus inducing the selective growth of the most aggressive cancer cells. This explains why many of the factors underlying a poor prognosis are induced in hypoxic/hypoglycemic conditions. Among these factors, a prominent role in several solid tumors is played by the class III β-tubulin gene (TUBB3). The study described here reveals that glucose deprivation enhances TUBB3 expression at both the gene and protein levels in A2780 ovarian cancer cells. In silico analysis of TUBB3 mRNA sequence predicted a putative binding site for the RNA-binding protein Hu antigen (HuR) in the 3′ flanking untranslated region. A hypoglycemic-dependent engagement of this site was shown using RNA pull-down and ribonucleoimmunoprecipitation techniques. Thereafter, HuR gene silencing revealed that TUBB3 translation is HuR dependent in hypoglycemia because HuR silencing inhibited the entry of TUBB3 mRNA into cytoskeletal and free polysomes. Finally, the clinical value of this finding was assessed in a clinical cohort of 46 ovarian cancer patients in whom it was found that HuR cytoplasmic staining was associated with high levels of TUBB3 and poor survival. Cancer Res; 70(14); 5891–900. ©2010 AACR.

Supplementary Figure Legend from Molecular Mechanisms of Patupilone Resistance

Supplementary Figure 1 from Molecular Mechanisms of Patupilone Resistance

Supplementary Figure 2 from HuR Regulates β-Tubulin Isotype Expression in Ovarian Cancer

Supplementary Figure 1 from HuR Regulates β-Tubulin Isotype Expression in Ovarian Cancer

We reported previously that Bcl-2 is paradoxically down-regulated in paclitaxel-resistant cancer cells. We reveal here that paclitaxel directly targets Bcl-2 in the loop domain, thereby facilitating the initiation of apoptosis. Molecular modeling revealed an extraordinary similarity between the paclitaxel binding sites in Bcl-2 and β-tubulin, leading us to speculate that paclitaxel could be mimetic of an endogenous peptide ligand, which binds both proteins. We tested the hypothesis that paclitaxel mimics Nur77, which, like paclitaxel, changes the function of Bcl-2. This premise was confirmed by Nur77 interacting with both paclitaxel targets (Bcl-2 and β-tubulin) and a peptide sequence mimicking the Nur77 structural region, thus reproducing the paclitaxel-like effects of tubulin polymerization and opening the permeability transition pore channel in mitochondria. This discovery could help in the development of novel anticancer agents with nontaxane skeleton as well as in identifying the clinical subsets responsive to paclitaxel-based therapy. [Cancer Res 2009;69(17):6906–14]

BackgroundT cell engagers are bispecific antibodies recognizing, with one moiety, the CD3ε chain of the T cell receptor and, with the other moiety, specific tumor surface antigens. Crosslinking of CD3 upon simultaneous binding to tumor antigens triggers T cell activation, proliferation and cytokine release, leading to tumor cell killing. Treatment with T cell engagers can be associated with safety liabilities due to on-target on-tumor, on-target off-tumor cytotoxic activity and cytokine release syndrome (CRS). Tyrosine kinases such as SRC, LCK or ZAP70 are involved in downstream signaling pathways after engagement of the T cell receptor and blocking these kinases might serve to abrogate T cell activation when required (online supplemental material 1). Dasatinib was previously identified as a potent kinase inhibitor that switches off CAR T cell functionality.MethodsUsing an in vitro model of target cell killing by human peripheral blood mononuclear cells, we assessed the effects of dasatinib combined with 2+1 T cell bispecific antibodies (TCBs) including CEA-TCB, CD19-TCB or HLA-A2 WT1-TCB on T cell activation, proliferation and target cell killing measured by flow cytometry and cytokine release measured by Luminex. To determine the effective dose of dasatinib, the Incucyte system was used to monitor the kinetics of TCB-mediated target cell killing in the presence of escalating concentrations of dasatinib. Last, the effects of dasatinib were evaluated in vivo in humanized NSG mice co-treated with CD19-TCB. The count of CD20+ blood B cells was used as a readout of efficacy of TCB-mediated killing and cytokine levels were measured in the serum.ResultsDasatinib concentrations above 50 nM prevented cytokine release and switched off-target cell killing, which were subsequently restored on removal of dasatinib. In addition, dasatinib prevented CD19-TCB-mediated B cell depletion in humanized NSG mice. These data confirm that dasatinib can act as a rapid and reversible on/off switch for activated T cells at pharmacologically relevant doses as they are applied in patients according to the label.ConclusionTaken together, we provide evidence for the use of dasatinib as a pharmacological on/off switch to mitigate off-tumor toxicities or CRS by T cell bispecific antibodies.

PURPOSE Glofitamab is a T-cell–engaging bispecific antibody possessing a novel 2:1 structure with bivalency for CD20 on B cells and monovalency for CD3 on T cells. This phase I study evaluated glofitamab in relapsed or refractory (R/R) B-cell non-Hodgkin lymphoma (B-NHL). Data for single-agent glofitamab, with obinutuzumab pretreatment ( Gpt) to reduce toxicity, are presented. METHODS Seven days before the first dose of glofitamab (0.005-30 mg), all patients received 1,000 mg Gpt. Dose-escalation steps were determined using a Bayesian continuous reassessment method with overdose control. Primary end points were safety, pharmacokinetics, and the maximum tolerated dose of glofitamab. RESULTS Following initial single-patient cohorts, 171 patients were treated within conventional multipatient cohorts and received at least one dose of glofitamab. This trial included heavily pretreated patients with R/R B-NHL; most were refractory to prior therapy (155; 90.6%) and had received a median of three prior therapies. One hundred and twenty-seven patients (74.3%) had diffuse large B-cell lymphoma, transformed follicular lymphoma, or other aggressive histology, and the remainder had indolent lymphoma subtypes. Five (2.9%) patients withdrew from treatment because of adverse events. Cytokine release syndrome occurred in 86 of 171 (50.3%) patients (grade 3 or 4: 3.5%); two (1.2%) patients experienced grade 3, transient immune effector cell–associated neurotoxicity syndrome-like symptoms. The overall response rate was 53.8% (complete response [CR], 36.8%) among all doses and 65.7% (CR, 57.1%) in those dosed at the recommended phase II dose. Of 63 patients with CR, 53 (84.1%) have ongoing CR with a maximum of 27.4 months observation. CONCLUSION In patients with predominantly refractory, aggressive B-NHL, glofitamab showed favorable activity with frequent and durable CRs and a predictable and manageable safety profile.

Background T cell bispecific antibodies (TCBs) are extremely potent T cell engagers, harboring a 2+1 format with one binder to the CD3e chain and two binders to specific tumor antigens. Crosslinking of CD3 with tumor antigens triggers T cell activation, proliferation and cytokine release, leading to tumor cell killing.1 2 TCB treatment is sometimes associated with safety liabilities due to on-target on-tumor, on-target off-tumor cytotoxic activity and cytokine release. Patients treated with TCBs may experience a Cytokine Release Syndrome (CRS), characterized by fever, hypotension and respiratory deficiency and associated with the release of pro-inflammatory cytokines such as IL-6, TNF-α, IFN-γ, and IL-1β.3 Off-tumor toxicity may occur if target antigens are expressed in healthy cells, which may potentially result in tissue damages and compromise the patient‘s safety. Rapid pharmacological blockade of T cell activation and proliferation is a promising approach to mitigate these life-threatening toxicities. Tyrosine kinases such as SRC, LCK or ZAP70 are involved in downstream signaling pathways after engagement of the T cell receptor and blocking these kinases might serve to abrogate T cell activation when required. Dasatinib was identified as a potent candidate that switches off CAR T cell functionality.4 5 Methods Using an in vitro model of target cell killing by human peripheral blood mononuclear cells, we assessed the reversible effects of dasatinib combined with CEA-TCB or HLA-A2-WT1-TCB on T cell activation and proliferation, target cell killing and cytokine release. At assay endpoints, T cell phenotype and target cell killing were measured by flow cytometry and supernatants were analyzed by Luminex to assess cytokine release. To determine the effective dose of dasatinib, the Incucyte system was used to follow kinetics of target cells killing by TCB in the presence of a dose response of dasatinib concentrations. Results 100 nM dasatinib prevented TCB-mediated target cell killing when added in the system upon restimulation of activated T cells (figure 1). Dasatinib concentrations above 50 nM fully switched off target cell killing (figure 2) which was restored upon removal of dasatinib. These data confirm that dasatinib act as a potent and reversible on/off switch for activated T cells at pharmacologically relevant doses as they are applied in patients according to the label.6 Conclusions Taken together, we provide evidence for the use of dasatinib as a pharmacological on/off switch to mitigate off-tumor toxicities or CRS by T cell engaging therapies. These data are being validated in vivo. References Bacac M, Fauti T, Sam J, Colombetti S, Weinzierl T, Ouaret D, et al. A novel carcinoembryonic antigen T-Cell Bispecific Antibody [CEA TCB] for the treatment of solid tumors. Clin Cancer Res 2016;22(13):3286–97. Bacac M, Klein C, Umana P. CEA TCB: A novel head-to-tail 2:1 T cell bispecific antibody for treatment of CEA-positive solid tumors. Oncoimmunology 2016;5(8):e1203498. Shimabukuro-Vornhagen A, Godel P, Subklewe M, Stemmler HJ, Schloser HA, Schlaak M, et al. Cytokine release syndrome. J Immunother Cancer 2018;6(1):56. Weber EW, Lynn RC, Sotillo E, Lattin J, Xu P, Mackall CL. Pharmacologic control of CAR-T cell function using dasatinib. Blood Advances 2019;3(5):711–7. Mestermann K, Giavridis T, Weber J, Rydzek J, Frenz S, Nerreter T, et al. The tyrosine kinase inhibitor dasatinib acts as a pharmacologic on/off switch for CAR T cells. Science Translational Medicine 2019;11(499):eaau5907. Wang X, Roy A, Hochhaus A, Kantarjian HM, Chen TT, Shah NP. Differential effects of dosing regimen on the safety and efficacy of dasatinib: retrospective exposure-response analysis of a Phase III study. Clinical pharmacology : advances and applications 2013;5:85–97.

Idasanutlin, a selective small-molecule MDM2 antagonist in phase 3 testing for refractory/relapsed AML, is a non-genotoxic oral p53 activator. The aim of this analysis is to examine the potential of idasanutlin to prolong the corrected QT (QTc) interval by evaluating the relationship between plasma idasanutlin concentration and QTc interval. Intensive plasma concentration QTc interval data were collected at the same timepoints, from three idasanutlin (RO5503781) phase 1 studies in patients with solid tumors and AML. QTc data in absolute values and changes from baseline (Δ) were analyzed for a potential association with plasma idasanutlin concentrations with a linear mixed effect model. Categorical analysis was also performed. A total of 282 patients were exposed to idasanutlin and had at least one observation of QTc and idasanutlin plasma concentration. There was no apparent increase of QTcF or ΔQTcF in a wide idasanutlin plasma concentration range, even at concentrations exceeding the exposure matching the dose adopted in the ongoing phase 3 study (300-mg BID). Categorical analysis did not detect a potential signal of QT prolongation. The concentration–QTc analysis indicates that idasanutlin does not prolong the QT interval within the targeted concentration range currently in consideration for clinical development.

From the whole plant of Euphorbia cyparissias, two new diterpenes based on jatrophane skeleton, named cyparissins A and B (1 and 2) were isolated. Their chemical structures were established through a combination of nuclear magnetic resonance spectroscopy and mass spectrometric methods. The new cyparissins A and B were tested to evaluate their ability to inhibit P-glycoprotein-mediated multidrug resistance and their cytotoxic activity against A2780 human ovarian cancer cells, both WT and ADR. Compounds 1 and 2 showed moderate inhibitory effects on P-glycoprotein while showing a significant concentration-depending cytotoxic activity for both cancer cell lines. These isolated compounds are based on a new chemical structure that expands the knowledge base for this class of bioactive metabolites.

// Silvia Prislei 1 , Enrica Martinelli 1 , Gian Franco Zannoni 1, 2 , Marco Petrillo 1 , Flavia Filippetti 1 , Marisa Mariani 3 , Simona Mozzetti 1 , Giuseppina Raspaglio 1 , Giovanni Scambia 1 , Cristiano Ferlini 1, 3 1 Department of Obstetrics and Gynecology, Catholic University of the Sacred Heart, Rome, Italy 2 Department of Pathology, Catholic University of the Sacred Heart, Rome, Italy 3 Reproductive Tumor Biology Research, Biomedical Lab, Department of Obstetrics and Gynecology, Danbury Hospital, Danbury, CT, USA Correspondence to: Silvia Prislei, e-mail: silvia.prislei@rm.unicatt.it Keywords: ZEB2, EMT, HuR, ovarian cancer Received: December 09, 2014 Accepted: May 05, 2015 Published: May 15, 2015 ABSTRACT ZEB2 is a key factor in epithelial-mesenchymal transition (EMT), a program controlling cell migration in embryonic development and adult tissue homeostasis. We demonstrated a role of ZEB2 in migration and anchorage-independent cell growth in ovarian cancer, as shown by ZEB2 silencing. We found that the RNA-binding protein HuR bound the 3′UTR of ZEB2 mRNA, acting as a positive regulator of ZEB2 protein expression. In Hey ovarian cell line, HuR silencing decreased ZEB2 and ZEB1 nuclear expression and impaired migration. In hypoglycemic conditions ZEB2 expression decreased, along with ZEB1, vimentin and cytoplasmic HuR, and a reduced cellular migration ability was observed. Analysis of ZEB2 and HuR expression in ovarian cancers revealed that nuclear ZEB2 is localized in tumor leading edge and co-localizes with cytoplasmic HuR. In a series of 143 ovarian cancer patients high expression of ZEB2 mRNA significantly correlated with a poor prognosis in term of both overall survival and progression- free survival. Moreover, at immunohistochemical evaluation, we found that prognostic significance of ZEB2 protein relies on its nuclear expression and co-localization with cytoplasmic HuR. In conclusion our findings indicated that nuclear ZEB2 may enhance progression of EMT transition and acquisition of an aggressive phenotype in ovarian cancer.

GBP1 and PIM1 are known to interact with a molar ratio 1:1. GBP1:PIM1 binding initiates a signaling pathway that induces resistance to common chemotherapeutics such as paclitaxel. Since GBP1 is a large GTPase which undergoes conformational changes in a nucleotide-dependent manner, we investigated the effect of GTP/GDP binding on GBP1:PIM1 interaction by using computational and biological studies. It resulted that only GTP decreases the formation of the GBP1:PIM1 complex through an allosteric mechanism, putting the bases for the identification of new compounds potentially able to revert resistance to paclitaxel.

Class III β-tubulin plays a prominent role in the development of drug resistance to paclitaxel by allowing the incorporation of the GBP1 GTPase into microtubules. Once in the cytoskeleton, GBP1 binds to prosurvival kinases such as PIM1 and initiates a signaling pathway that induces resistance to paclitaxel. Therefore, the inhibition of the GBP1:PIM1 interaction could potentially revert resistance to paclitaxel. A panel of 44 4-azapodophyllotoxin derivatives was screened in the NCI-60 cell panel. The result is that 31 are active and the comparative analysis demonstrated specific activity in paclitaxel-resistant cells. Using surface plasmon resonance, we were able to prove that NSC756093 is a potent in vitro inhibitor of the GBP1:PIM1 interaction and that this property is maintained in vivo in ovarian cancer cells resistant to paclitaxel. Through bioinformatics, molecular modeling, and mutagenesis studies, we identified the putative NSC756093 binding site at the interface between the helical and the LG domain of GBP1. According to our results by binding to this site, the NSC756093 compound is able to stabilize a conformation of GBP1 not suitable for binding to PIM1.

Introduction: CD20-TCB (RG6026) is a novel T-cell-engaging bispecific (TCB) antibody with a '2:1' molecular format that comprises two fragment antigen binding regions that bind CD20 (on the surface of B cells) and one that binds CD3 (on the surface of T cells). CD20-TCB offers the potential for increased tumor antigen avidity, rapid T-cell activation, and enhanced tumor cell killing versus other bispecific formats. The safety, tolerability, pharmacokinetics, biomarkers, and antitumor activity of CD20-TCB are currently being investigated in a multicenter Phase I dose-escalation trial (NP30179; NCT03075696). We recently presented preliminary clinical data demonstrating promising clinical activity in relapsed or refractory (R/R) non-Hodgkin lymphoma (NHL) patients with indolent or aggressive disease (Dickinson et al. ICML 2019). Here, we present preliminary blood and tissue biomarker analyses to explore modes of action, support optimal biological dose selection, and identify potential outcome predictors. Methods: For biomarker analyses, we performed immune profiling of peripheral blood by flow cytometry, analyzed plasma cytokine levels by ELISA, and characterized baseline and on-treatment tumor biopsies by immunohistochemistry/immunofluorescence assays and RNA sequencing. Biomarker data were obtained from 122 patients dosed with 0.005-25mg CD20-TCB. Results: CD20-TCB infusion led to a rapid and transient reduction in T cells in the peripheral circulation (T-cell margination) in all patients. T-cell margination reached nadir 6 hours after the first CD20-TCB infusion, and showed a strong association with CD20-TCB dose and receptor occupancy (RO%; as determined by Djebli et al. ASH 2019). Interestingly, rebound of T cells 160 hours after the first CD20-TCB infusion was associated with response to treatment. Responding patients showed long-term T-cell activation after the first infusion of CD20-TCB at doses from 0.6mg and above. T-cell activation was demonstrated by 2-4-fold elevation of T-cell activation markers such as Ki67, HLA-DR, PD-1, ICOS, OX40, and 4-1BB, which was sustained up to Cycle 5 (105 days). Analysis of paired pre- and on-treatment tumor biopsies (n=6) obtained before and 2-3 weeks after the first dose of CD20-TCB showed evidence of T-cell-mediated tumor cell killing. Analysis of archival and pre-treatment tumor biopsies (n=80) revealed that clinical responses were achieved irrespective of the amount of tumor T-cell infiltration at baseline. In contrast, preliminary baseline bulk tumor RNA sequencing data (n=46) showed upregulation of gene signatures associated with cell proliferation/Myc and T-cell subsets (effector vs exhausted-like) in non-responding patients. Conclusions: In this study, we demonstrated the mode of action of CD20-TCB, a novel bispecific antibody with promising clinical activity in R/R NHL. We also demonstrated that biomarker data on T-cell activation can support dose finding in conjunction with pharmacokinetics. Additional analysis is ongoing to evaluate response predictors and better characterize the population that will benefit most from T-cell mediated therapies. Disclosures Bröske: Roche: Employment, Equity Ownership. James:A4P Consulting Ltd: Consultancy. Belousov:Roche: Employment. Gomez:F. Hoffmann-La Roche Ltd: Employment. Canamero:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Ooi:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Grabole:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Wilson:F. Hoffmann-La Roche Ltd: Employment. Korfi:F. Hoffmann-La Roche Ltd: Consultancy. Kratochwil:F. Hoffmann-La Roche Ltd: Employment. Morcos:Roche: Employment, Equity Ownership. Ferlini:Roche: Employment, Equity Ownership. Thomas:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Dimier:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Moore:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Bacac:Roche: Employment, Equity Ownership, Patents & Royalties: Patents, including the one on CD20-TCB. Weisser:Pharma Research and Early Development Roche Innovation Center Munich: Employment, Equity Ownership, Patents & Royalties. Dickinson:Merck Sharpe and Dohme: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; GlaxoSmithKline: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. OffLabel Disclosure: CD20-TCB (also known as RG6026, RO7082859) is a full-length, fully humanized, immunoglobulin G1 (IgG1), T-cell-engaging bispecific antibody with two fragment antigen binding (Fab) regions that bind to CD20 (on the surface of B cells) and one that binds to CD3 (on the surface of T cells) (2:1 format). The 2:1 molecular format of CD20-TCB, which incorporates bivalent binding to CD20 on B cells and monovalent binding to CD3 on T cells, redirects endogenous non-specific T cells to engage and eliminate malignant B cells. CD20-TCB is an investigational agent.

Introduction: CD20-TCB (RG6026) is a novel T-cell-engaging bispecific (TCB) antibody with a '2:1' molecular format that comprises two fragment antigen binding regions that bind CD20 (on the surface of B cells) and one that binds CD3 (on the surface of T cells). CD20-TCB offers the potential for increased tumor antigen avidity, rapid T-cell activation, and enhanced tumor cell killing versus other bispecific formats. An ongoing Phase I dose-escalation study (NP30179; NCT03075696) has shown promising antitumor activity and acceptable safety in relapsed or refractory (R/R) non-Hodgkin lymphoma (NHL) patients (pts) (Dickinson et al. ICML 2019). We investigated population pharmacokinetics (popPK) and exposure-response (E-R) relationships for CD20-TCB in NP30179. Methods: Indolent (i) and aggressive (a) R/R NHL pts received CD20-TCB doses of 0.005 to 25mg every 2 or 3 weeks following single 1000mg obinutuzumab (G) pre-treatment (Gpt) on Cycle 1 Day −7 to mitigate for cytokine release syndrome (CRS). Serial and spare PK data collected from pts were used to develop a popPK model in NONMEM v7.4. Physiologically relevant covariates were investigated for their potential influence on CD20-TCB PK variability. Using the previously established G popPK model (Gibiansky et al. CPT Pharmacometrics Syst Pharmacol 2014;3:e144), full G concentration-time profiles were constructed in order to estimate CD20-TCB receptor occupancy (RO%) in the presence of G concentrations competing for CD20 receptors over time. E-R relationships between CD20-TCB time-averaged RO% (AvgRO%) up to Cycle 3 Day 1 and objective response rate (ORR) and complete response rate (CRR) were investigated in aNHL pts who reached Cycle 3 Day 1, and the relationship between CD20-TCB AvgRO% over the first 24 hours (as the majority of events occurred within the first 24 hours) and CRS, the most common safety event, as defined by Lee et al. (Blood 2014;124:188-95), was investigated in iNHL and aNHL pts combined using logistic regression. Results: The popPK analysis included 139 iNHL and aNHL pts with at least one PK sample. The E-R analysis for efficacy included 76 aNHL pts with PK and efficacy data at Cycle 3 Day 1. The E-R analysis for safety included 121 iNHL and aNHL pts with PK and safety data. CD20-TCB PK was best described using a two-compartment PK model with linear clearance. Body weight had a statistically significant influence on PK and was retained using theory-based allometric scaling. There were no obvious differences in PK between iNHL and aNHL pts. In aNHL pts, logistic regression analyses demonstrated a significant positive E-R relationship between AvgRO% up to Cycle 3 Day 1 and efficacy (ORR and CRR, p=0.007; Figure 1 for CRR). In the highest tertile of AvgRO% (≥0.48%), the observed ORR was 76% versus 38.5% ( Conclusions: PopPK and E-R relationships are characterized for the novel CD20/CD3 TCB antibody CD20-TCB and are being used to support optimal biological-dose selection as a single agent in ongoing combination investigations (Morschhauser et al. ASH 2019; Hutchings et al. ASH 2019). Disclosures Djebli: F. Hoffmann-La Roche Ltd: Employment. Jaminion:F. Hoffmann-La Roche Ltd: Employment. Laurent:F. Hoffmann-La Roche Ltd: Employment. Mercier:F. Hoffmann-La Roche Ltd: Employment. Kratochwil:F. Hoffmann-La Roche Ltd: Employment. Bröske:Roche: Employment, Equity Ownership. Dimier:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Ferlini:Roche: Employment, Equity Ownership. Moore:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Weisser:Pharma Research and Early Development Roche Innovation Center Munich: Employment, Equity Ownership, Patents & Royalties. Morcos:Roche: Employment, Equity Ownership. OffLabel Disclosure: CD20-TCB (also known as RG6026, RO7082859) is a full-length, fully humanized, immunoglobulin G1 (IgG1), T-cell-engaging bispecific antibody with two fragment antigen binding ('Fab') regions that bind to CD20 (on the surface of B cells) and one that binds to CD3 (on the surface of T cells) (2:1 format). The 2:1 molecular format of CD20-TCB, which incorporates bivalent binding to CD20 on B cells and monovalent binding to CD3 on T cells, redirects endogenous non-specific T cells to engage and eliminate malignant B cells. CD20-TCB is an investigational agent.

CD20-TCB (RG6026) is a novel T-cell-engaging bispecific (TCB) antibody with a '2:1' molecular format that comprises two fragment antigen binding regions that bind CD20 (on the surface of B cells) and one that binds CD3 (on the surface of T cells). CD20-TCB offers the potential for increased tumor antigen avidity, rapid T-cell activation, and enhanced tumor cell killing versus other bispecific formats. CD20-TCB has demonstrated highly promising single-agent activity in relapsed or refractory (R/R) B-cell non-Hodgkin lymphoma (B-NHL) patients (pts) (Dickinson et al. ICML 2019). Preclinical data demonstrate CD20-TCB-induced programmed cell death protein 1 (PD-1) and programmed cell death-ligand-1 (PD-L1) upregulation on T cells and tumor cells. We hypothesized that the combination of T-cell engagement by CD20-TCB and PD-L1 inhibition by atezolizumab could lead to additive anti-tumor activity in B-NHL. We report preliminary data from NP39488 (NCT03533283), an ongoing Phase Ib study evaluating the safety, tolerability, pharmacokinetics, and preliminary efficacy (objective response rate [ORR] and complete response [CR] rate per modified Lugano 2014 criteria) of CD20-TCB in combination with atezolizumab in R/R B-NHL pts. A single dose of 1000mg obinutuzumab (G) is administered on Day −7 of Cycle 1 as pretreatment (Gpt) to mitigate for potential cytokine release syndrome (CRS). CD20-TCB is initiated on Day 1 of Cycle 1 and given in a q3w schedule. From Cycle 2 onwards, atezolizumab (1200mg) is added and given on the same day as CD20-TCB. CD20-TCB dose-escalation is ongoing and is guided by the modified continual reassessment method-escalation with overdose control (mCRM-EWOC). As of June 25, 2019, 38 pts with aggressive B-NHL (n=33; diffuse large B-cell lymphoma [DLBCL], transformed [tr] follicular lymphoma [FL], primary mediastinal large B-cell lymphoma, mantle cell lymphoma, tr lymphoplasmacytic lymphoma, tr Waldenstrom`s macroglobulinemia) or indolent B-NHL (n=5; FL) had received CD20-TCB doses from 0.07mg to currently 6mg. Pts (52.6% male) had a median age of 67 years (range: 38-82) and a median of three prior treatment lines (range: 1−10); 84% had refractory B-NHL. Two dose-limiting toxicities (Grade [Gr] 3 tumor flare at 6mg during Cycle 1 and Gr 3 myopathy at 1.8mg during Cycle 2) were transient and resolved completely. The most frequent adverse event (AE) was CRS (42%; 16/38 pts), with 24% Gr 1 (n=9), 18% Gr 2 (n=7), and no Gr ≥3 (according to Lee criteria, Lee et al. Blood 2014;124:188-95). The most common AEs (>20%) were pyrexia (37%), anemia (29%), fatigue (24%), neutropenia (21%), diarrhea (21%), and decreased appetite (21%). The most common Gr ≥3 AEs (>10%) were neutropenia (18%) and anemia (13%), with a single Gr 5 unrelated pneumonia. Three pts experienced a transient Gr ≥3 neurotoxicity (Gr 4 polyneuropathy, Gr 3 trigeminal nerve herpes zoster infection, and Gr 3 post-infection encephalopathy), all of which resolved. Thirty-six pts reached their first response assessment or withdrew early and were eligible for efficacy analysis. Across all doses, ORR and CR rates by investigator assessment were 36% (13/36 pts) and 17% (6/36), respectively (indolent NHL: 4/5 and 3/5 pts; aggressive NHL: 9/31 and 3/31 pts). All CRs are ongoing at the time of abstract submission. CD20-TCB exposure and receptor occupancy (RO%) increased dose-dependently across the dose-range evaluated, and are expected to be further optimized (Djebli et al. ASH 2019). At the higher CD20-TCB doses investigated, a trend towards increased clinical activity was observed (ORR of 60% [9/15 pts] in the 4mg and 6mg cohorts combined). The combination of CD20-TCB and atezolizumab has manageable safety in R/R B-NHL pts. No new safety signals or signs of increased immune-related AEs were detected, and the overall safety profile was consistent with that reported with single-agent CD20-TCB (Dickinson et al. ICML 2019). Dose escalation is ongoing and aims to optimize the dose and schedule of CD20-TCB when combined with atezolizumab using the established exposure-response model for CD20-TCB (Djebli et al. ASH 2019). Updated safety, efficacy, and biomarker data will be presented. Disclosures Hutchings: Genmab: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Research Funding; Celgene: Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Janssen: Research Funding; Incyte: Research Funding. Gritti:Roche: Other: Not stated; Abbvie: Other: Not stated; Becton Dickinson: Other: Not stated; Autolus Ltd: Honoraria. Sureda:Sanofi: Honoraria; Amgen: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria; Gilead: Honoraria; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria; BMS: Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel Support. Terol:Roche: Consultancy; Abbvie: Consultancy; Astra Zeneca: Consultancy; Janssen: Consultancy, Research Funding; Gilead: Research Funding. Dyer:Roche: Research Funding. Iacoboni:Novartis: Consultancy, Honoraria; Roche: Honoraria; Janssen: Honoraria; Abbvie: Honoraria; Celgene: Honoraria. Townsend:Roche: Consultancy, Honoraria. Bacac:Roche: Employment, Equity Ownership, Patents & Royalties: Patents, including the one on CD20-TCB. Bröske:Roche: Employment, Equity Ownership. Dimier:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Ferlini:Roche: Employment, Equity Ownership. Keelara:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Lahr:Roche: Employment, Honoraria. Lechner:Roche: Employment, Other: Roche shareholder. Moore:Roche: Employment, Equity Ownership. Morcos:Roche: Employment, Equity Ownership. Panchal:Roche: Employment. Weisser:Pharma Research and Early Development Roche Innovation Center Munich: Employment, Equity Ownership, Patents & Royalties. OffLabel Disclosure: CD20-TCB (also known as RG6026, RO7082859) is a full-length, fully humanized, immunoglobulin G1 (IgG1), T-cell-engaging bispecific antibody with two fragment antigen binding (Fab) regions that bind to CD20 (on the surface of B cells) and one that binds to CD3 (on the surface of T cells) (2:1 format). The 2:1 molecular format of CD20-TCB, which incorporates bivalent binding to CD20 on B cells and monovalent binding to CD3 on T cells, redirects endogenous non-specific T cells to engage and eliminate malignant B cells. CD20-TCB is an investigational agent.

CD20-TCB (RG6026) is a novel T-cell-engaging bispecific (TCB) antibody with a '2:1' molecular format comprising two fragment antigen binding regions that bind CD20 (on the surface of B cells) and one that binds CD3 (on the surface of T cells). CD20-TCB offers the potential for increased tumor antigen avidity, rapid T-cell activation, and enhanced tumor cell killing versus other bispecific formats, and the ability to combine with another CD20-targeted agent. Preclinical studies of concurrent therapy with CD20-TCB plus obinutuzumab (G) in diffuse large B-cell lymphoma (DLBCL) models demonstrate strong and sustained tumor regression driven by multiple mechanisms of action. These include induction of direct tumor cell death and antibody-dependent cellular cytotoxicity/cellular phagocytosis mediated by G, as well as recruitment of T-cells into the tumor and T-cell cytotoxicity mediated by CD20-TCB. NP30179 (NCT03075696) is a multicenter Phase I/Ib dose-escalation trial investigating the safety, tolerability, pharmacokinetics, biomarker responses, and anti-tumor activity (assessed by objective response rate [ORR] and complete response [CR] rate per modified Lugano 2014 criteria) of CD20-TCB in relapsed or refractory (R/R) B-cell non-Hodgkin lymphoma (NHL) patients (pts). For the first time, we report preliminary data from Arm B, evaluating dual CD20-targeted therapy with concurrent CD20-TCB and G. All pts receive a single dose of 1000mg G as pre-treatment (Gpt) 7 days before the start of CD20-TCB therapy (Cycle 1) to mitigate cytokine release syndrome (CRS). From Cycle 2 onwards, 1000mg G is administered on the same day as CD20-TCB, which constitutes the start of an initial 28-day dose-limiting toxicity (DLT) window, in 3-weekly cycles. Pts receive escalating doses of CD20-TCB, guided by a model implementing the Bayesian continuous reassessment method with overdose control. As of May 22, 2019, a total of 28 pts with R/R aggressive (a) NHL (DLBCL/primary mediastinal large B-cell lymphoma/transformed follicular lymphoma [FL]/mantle cell lymphoma/Richter´s transformation; n=22) or FL (n=6) had received concurrent G in combination with CD20-TCB doses ranging from 0.6 to 16mg for 8-12 cycles. Median age was 65 years (range, 34-81), 15 (54%) were male, 19 (68%) were refractory to prior therapy, and median prior lines of therapy was 2 (range, 1-6). Twenty-three CRS events (according to Lee criteria, Lee et al. Blood 2014) occurred in 16 (57%) pts (maximum Grade [Gr]: Gr 1, 5 [18%]; Gr 2, 9 [32%]; Gr 3, 1 [4%]; Gr 4, 1 [4%]). CRS events were confined to Cycle 1 in all but two pts. Neurotoxicity was rare (Gr 1, 4 [14%]; Gr 2, 2 [7%]; Gr 3, 1 [4%]) and all events resolved. Apart from CRS, the most frequent adverse events were anemia (all Gr, 6 [21%]; Gr 3, 3 [11%]), thrombocytopenia (all Gr, 6 [21%]; Gr ≥3, 3 [11%]; no hemorrhages reported), neutropenia (all Gr, 4 [14%]; Gr ≥3, 3 [11%]), pyrexia (all Gr, 4 [14%], all Gr 1-2), and hypokalemia (all Gr, 4 [14%]; Gr ≥3, 1 [4%]). No DLTs were reported and no new safety signals were observed. The overall safety profile overlapped with that reported in the single arm of the same study. Twenty-one pts reached their first response assessment or withdrew early and were eligible for efficacy analysis. Overall, the ORR and CR rate by investigator assessment was 48% [10/21 pts] and 43% [9/21], respectively (aNHL: ORR, 38% [6/16]; CR, 31% [5/16]; FL: ORR and CR, 80% [4/5]). CD20-TCB exposure and receptor occupancy (RO%) increased dose-dependently across the investigated dose range, and consistent with the RO%-efficacy model (Djebli et al. ASH 2019), clinically relevant CD20-TCB RO% and increased clinical activity was observed at a dose of 16mg when combined with concurrent G. In the 16mg cohort that included 10 R/R pts, 70% of whom were refractory to prior therapy and median prior lines of therapy was 4, the ORR and CR rate were 90% (9/10 pts) and 80% (8/10), respectively (aNHL: CR, 71% [5/7]; FL: CR, 100% [3/3]), and all CRs were ongoing at the time of abstract submission. This is the first study to demonstrate that CD20-TCB can be safely combined with an anti-CD20 monoclonal antibody and further supports the promise of the '2:1' format for allowing combination therapy with therapeutic levels of other anti-CD20 antibodies, such as G. CD20-TCB plus G provides highly promising clinical activity in heavily pre-treated R/R B-cell NHL. Updated clinical and biomarker data will be presented. Disclosures Morschhauser: Janssen: Honoraria; BMS: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; Epizyme: Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Carlo-Stella:AstraZeneca: Honoraria; ADC Therapeutics: Consultancy, Other: Travel, accommodations, Research Funding; Servier: Consultancy, Honoraria, Other: Travel, accommodations; Rhizen Pharmaceuticals: Research Funding; Boehringer Ingelheim: Consultancy; Novartis: Consultancy, Research Funding; Janssen Oncology: Honoraria; Takeda: Other: Travel, accommodations; Sanofi: Consultancy, Research Funding; Genenta Science srl: Consultancy; F. Hoffmann-La Roche Ltd: Honoraria, Other: Travel, accommodations, Research Funding; Amgen: Honoraria; MSD: Honoraria; Janssen: Other: Travel, accommodations; Celgene: Research Funding; BMS: Honoraria. Salles:Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Educational events; Autolus: Consultancy, Membership on an entity's Board of Directors or advisory committees; Epizyme: Consultancy, Honoraria; Roche, Janssen, Gilead, Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Educational events; BMS: Honoraria; Novartis, Servier, AbbVie, Karyopharm, Kite, MorphoSys: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Educational events; Merck: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Other: Educational events. Hutchings:Janssen: Research Funding; Pfizer: Research Funding; Incyte: Research Funding; Celgene: Research Funding; Genmab: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Iacoboni:Celgene: Honoraria; Janssen: Honoraria; Novartis: Consultancy, Honoraria; Abbvie: Honoraria; Roche: Honoraria. Sureda:Amgen: Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Honoraria, Speakers Bureau; Roche: Honoraria; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria; Sanofi: Honoraria; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel Support; Gilead: Honoraria; Novartis: Honoraria. Crump:Servier: Consultancy; F. Hoffmann-La Roche Ltd: Consultancy, Research Funding; Kite/Gilead: Consultancy. Martinez-Lopez:Novartis: Honoraria, Other: Advisory boards; Janssen: Honoraria, Other: Advisory boards and Non-Financial Support ; Incyte: Honoraria, Other: Advisory boards; VIVIA Biotech: Honoraria; Celgene: Honoraria, Other: Advisory boards and Non-Financial Support ; Amgen: Honoraria, Other: Non-Financial Support ; F. Hoffmann-La Roche Ltd: Honoraria; BMS: Honoraria, Other: Advisory boards. Thomas:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Morcos:Roche: Employment, Equity Ownership. Ferlini:Roche: Employment, Equity Ownership. Keelara:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Bröske:Roche: Employment, Equity Ownership. Bacac:Roche: Employment, Equity Ownership, Patents & Royalties: Patents, including the one on CD20-TCB. Dimier:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Moore:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Weisser:Pharma Research and Early Development Roche Innovation Center Munich: Employment, Equity Ownership, Patents & Royalties. Dickinson:Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; GlaxoSmithKline: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Merck Sharpe and Dohme: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. OffLabel Disclosure: CD20-TCB (also known as RG6026, RO7082859) is a full-length, fully humanized, immunoglobulin G1 (IgG1), T-cell-engaging bispecific antibody with two fragment antigen binding ('Fab') regions that bind to CD20 (on the surface of B cells) and one that binds to CD3 (on the surface of T cells) (2:1 format). The 2:1 molecular format of CD20-TCB, which incorporates bivalent binding to CD20 on B cells and monovalent binding to CD3 on T cells, redirects endogenous non-specific T cells to engage and eliminate malignant B cells. CD20-TCB is an investigational agent.

Purpose: Colorectal cancer is one of the deadliest diseases in Western countries. To predict the outcome of therapy, we assessed the role of class III (TUBB3) and class V β-tubulin (TUBB6) as predictive biomarkers. Experimental Design: Using immunohistochemistry and nanofluidics, the expression of TUBB3 and TUBB6 was assessed in two cohorts of 180 and 134 patients, respectively. The CYP17A1 RS743572 was genotyped to identify GG carriers with enhanced androgen levels. TUBB3 and TUBB6 were investigated in 22 colorectal cancer cell lines in basal conditions and after serum starvation, the latter serving as activator of this prosurvival pathway. To ascertain the role of androgen receptor (AR) in such regulation, we silenced AR and checked TUBB3 and TUBB6 expression and sensitivity to chemotherapy. Results: There was a link between poor survival, the expression of TUBB3/TUBB6, and AR only in females. Conversely, only in males carriers of the GG phenotype exhibited the worst outcome. Importantly, male cell lines were resistant to serum starvation and exhibited higher levels of TUBB6, thereby suggesting that the pathway is activated by androgens. In female cells this phenomenon was absent. In both genders, AR was the main driver of TUBB3/TUBB6 expression, as constitutive silencing of AR was associated with downregulation of TUBB3/TUBB6 expression and increased sensitivity to oxaliplatin and SN-38. Conclusions: The involvement of androgens in the TUBB3 pathway opens the way for clinical trials to assess the efficacy of antiandrogens for increasing the efficacy of chemotherapy in male colorectal cancer patients. Clin Cancer Res; 18(10); 2964–75. ©2012 AACR.

Among the drugs targeting microtubule functions by interfering with tubulin subunits, epothilones represent a class of anticancer agents which recently entered clinical development. Although epothilones share mechanisms of action similar to taxanes, they have non-overlapping mechanisms of resistance; in particular, while overexpression of class III β-tubulin plays a major role in taxane resistance, epothilones display their highest efficacy in class III β-tubulin overexpressing malignancies. Three compounds belonging to this family (patupilone, ixabepilone and sagopilone), have been actively investigated in clinical trials, and some of them are at an advanced stage of development. This review provides a comprehensive analysis of the available literature on epothilones, focusing on their clinical development and potential as an additional weapon in the arsenal against tumors.

Class III β-tubulin (TUBB3) is a prominent mechanism of drug resistance expressed in a variety of solid tumors and particularly in lung and ovarian cancer. In the classical view, TUBB3 expression and drug resistance have been linked, and together they have been associated with a perturbation in microtubule dynamics. In keeping with this observation, TUBB3 was associated with drug resistance only when chemotherapy included a taxane in its chemical composition. In this review, we demonstrate that the classical supposition about TUBB3 is not correct, and that instead TUBB3 expression is linked to drug resistance as a complex survival mechanism activated by microenvironmental conditions such as poor nutrient supply and hypoxia.

Epithelial ovarian cancer is the leading cause of death for gynecological cancer in most of the Western world; lethality ensues from the occurrence of occult metastasis within the peritoneal cavity, a process requiring the acquisition of capacity for migration and invasiveness by ovarian tumor cells (metastatic phenotype), and characterized by a complex series of interrelated cellular events. Unlike most carcinomas that dedifferentiate during neoplastic progression with loss of epithelial E-cadherin (epithelial to mesenchymal transition, EMT), ovarian carcinomas undergo transition to a more epithelial phenotype, early in tumor progression, with increased E-cadherin expression. Subsequent reacquisition of mesenchymal features is observed in late-stage tumors, and loss of E-cadherin expression or function is a factor in ovarian cancer progression. Changes in E-cadherin expression are indicative of the phenotypic plasticity that occurs in ovarian cancer, with a variety of signal transduction pathways impinging on the regulation of E-cadherin levels or subcellular distribution. Among them, the Snail transcription family, consisting of members SNAIL and SLUG, is thought to be mainly involved in the repression of E-cadherin expression, leading to EMT. E-cadherin, SNAIL, and SLUG also represent crucial targets of estrogen signaling. In this review, we discuss recent advances in the understanding of the role of estrogen signaling in the complex network underlying the phenotypic plasticity in ovarian cancer. Insight into the mechanisms involved will allow rational drug designs, aimed at the molecules critical to cellular signaling.

Glycosylation, one of the most common post translational modifications (PTMs) of proteins, is often associated with carcinogenesis and tumor malignancy. Ovarian cancer is the sixth cause of cancer-related death in Western countries. Currently, it is treated by debulking surgery followed by chemotherapy based on paclitaxel, alone or in combination with other drugs. However, chemoresistance represents a major obstacle to positive clinical outcome. We used two approaches, Multiplexed Proteomics (MP) technology and Multilectin Affinity Chromatography (MAC) to characterize the glycoproteome of the human ovarian cancer cell line A2780 and its paclitaxel resistant counterpart A2780TC1. Furthermore proteins were separated by traditional 2DE or DIGE and identified by MS (MALDI TOF or LC MS/MS). Seventy glycoproteins were successfully identified in ovarian cancer cells and 10 were found to be differentially expressed between sensitive and resistant cell lines. We focused on four glycoproteins (tumor rejection antigen (gp96) 1, triose phosphate isomerase, palmitoyl-protein thioesterase 1 precursor and ER-associated DNAJ) which were remarkably upregulated in A2780TC1 compared to A2780 cell line and which may represent biomarkers for paclitaxel resistance in ovarian cancer.

This study was aimed at evaluating the potential application of benzophenanthridine alkaloids, sanguinarine and cheleritrine, in the therapy of melanoma cancer. In vitro antiproliferative activity of sanguinarine was higher than that of cheleritrine against the B16 melanoma 4A5 cells. Both agents were able to produce DNA breaks, and the DNA unwinding assay showed that they act as DNA intercalating agents. Sanguinarine was selected for determination of its in vivo preclinical efficacy. Oral treatment with sanguinarine reduced the tumor burden in a transplantable murine tumor grown in a syngeneic host (B16 melanoma 4A5 in C57BL/6 mice), and in a human tumor xenograft grown in immunodeficient mice (A375 human melanoma in athymic nude mice). In A375 tumors a significant decrease in the proliferation marker Ki67, and a reduction in the activated mitogen-activated protein kinases (p-p44/42 MAPK), and in protein kinase B (pAKT) were also observed. Three out of eleven A375-bearing treated mice were tumor-free at the end of treatment, and did not develop any tumor after a further, treatment-free, observation period of 60 days. Sanguinarine also showed a striking antiangiogenic activity in mice. Data from the present study support the concept that sanguinarine can be effective in melanoma skin cancer.

Microtubules are involved in a variety of essential cell functions. Their role during mitosis has made them a target for anti-cancer drugs. However development of resistance has limited their use. It has been established that enhanced beta3-tubulin expression is correlated with reduced response to antimicrotubule agent-based chemotherapy or worse outcome in a variety of tumor settings. However little is known regarding the regulation of beta3-tubulin expression. We investigated the regulatory mechanisms of expression of beta3-tubulin in the MCF-7 cell line, a model of hormone-dependent breast cancer. Exposure of MCF-7 cells to estradiol was found to induce beta3-tubulin mRNA as well as beta3-tubulin protein expression. Conversely, we did not observe induction of beta3-tubulin mRNA by estradiol in MDA-MB-231 cells which are negative for the estrogen receptor (ER). In order to determine whether beta3-tubulin up-regulation is mediated through the ER pathway, MCF-7 cells were exposed to two ER modulators. Exposure to tamoxifen, a selective estrogen receptor modulator, completely abolished the beta3-tubulin mRNA induction due to estradiol in MCF-7 cells. This result was confirmed with fulvestrant, a pure antagonist of ER. These results demonstrate that the effect of estradiol on beta3-tubulin transcription is mediated through an ER dependent pathway.

Deregulated signaling through the epidermal growth factor receptor (EGFR) is involved in chemoresistance. To identify the molecular determinants of sensitivity to the EGFR inhibitor gefitinib (Iressa, ZD1839) in chemoresistance, we compared the response of matched chemosensitive and chemoresistant glioma and ovarian cancer cell lines. We found that chemoresistant cell lines were 2- to 3-fold more sensitive to gefitinib growth-inhibitory effects, because of decreased proliferation rather than survival. Sensitivity to gefitinib correlated with overexpression and constitutive phosphorylation of HER2 and HER3, but not EGFR, altered HER ligand expression, and enhanced activation of EGF-triggered EGFR pathway. No activating mutations were found in EGFR. Gefitinib fully inhibited EGF-induced and constitutive Akt activation only in chemoresistant cells. In parallel, gefitinib downregulated constitutively phosphorylated HER2 and HER3, and activated GSK3beta with a concomitant degradation of cyclin D1. Ectopically overexpressed HER2 on its own was insufficient to sensitize chemonaive cells to gefitinib. pHER3 coimmunoprecipitated with p85-PI3K in chemoresistant cells and gefitinib dissociated these complexes. siRNA-mediated inhibition of HER3 decreased constitutive activation of Akt and sensitivity to gefitinib in chemoresistant cells. Our study indicates that in chemoresistant cells gefitinib inhibits both an enhanced EGF-triggered pathway and a constitutive HER3-mediated Akt activation, indicating that inhibition of HER3 together with that of EGFR could be relevant in chemorefractory tumors. Furthermore, in combination experiments gefitinib enhanced the effects of coadministered drugs more in chemoresistant than chemosensitive ovarian cancer cells. Combined treatment might be therapeutically beneficial in chemoresistant tumors from ovary and likely from other tissues.

Objectives Chemotherapy is the preferred therapeutic approach for the therapy of advanced ovarian cancer, but a successful long-term treatment is prevented by the development of drug resistance. Recent works have underlined the involvement of non-coding RNAs, microRNAs (miRNAs) in cancer development, with several conjectures regarding their possible involvement in the evolution of drug resistance. This work was aimed to identify selected microRNAs involved in the development of chemoresistance in ovarian cancer. Methods High-throughput analysis of the miRNA profile in a panel of paclitaxel- (A2780TAX, A2780TC1 and A2780TC3) and cisplatin-resistant (A2780CIS) cells was assessed using a microarray platform and subsequent validation with qPCR and Northern blots. Downstream target validation was performed for miR-130a and the target M-CSF.] Results Six miRNAs (let-7e, miR-30c, miR-125b, miR-130a and miR-335) were always diversely expressed in all the resistant cell lines. Let-7e was upregulated in A2780TAX cells, while it was downregulated in the other resistant cell lines. The opposite phenomenon was obtained for miR-125b, which was downregulated in A2780TAX and upregulated in the other cell lines. The miR-30c, miR-130a and miR-335 were downregulated in all the resistant cell lines, thereby suggesting a direct involvement in the development of chemoresistance. Finally downstream target validation was proven for the miR-130a, whose downregulation was linked to the translational activation of the M-CSF gene, a known resistance factor for ovarian cancer. Conclusions Our results indicate that ovarian cancer drug resistance is associated with a distinct miRNA fingerprint, and miRNA microarrays could represent a prognostic tool to monitor the chemotherapy outcome.

Class III β-tubulin (TUBB3) has been discovered as a marker of drug resistance in human cancer. To get insights into the mechanisms by which this protein is involved in drug resistance, we analyzed TUBB3 in a panel of drug-sensitive and drug-resistant cell lines. We identified two main different isoforms of TUBB3 having a specific electrophoretic profile. We showed that the apparently higher molecular weight isoform is glycosylated and phosphorylated and it is localized in the cytoskeleton. The apparently lower molecular weight isoform is instead found exclusively in mitochondria. We observed that levels of phosphorylation and glycosylation of TUBB3 are associated with the resistant phenotype and compartmentalization into cytoskeleton. By two-dimensional nonreduced/reduced SDS-PAGE analysis, we also found that TUBB3 protein in vivo forms protein complexes through intermolecular disulfide bridges. Through TUBB3 immunoprecipitation, we isolated protein species able to interact with TUBB3. Following trypsin digestion, these proteins were characterized by mass spectrometry analysis. Functional analysis revealed that these proteins are involved in adaptation to oxidative stress and glucose deprivation, thereby suggesting that TUBB3 is a survival factor able to directly contribute to drug resistance. Moreover, glycosylation of TUBB3 could represent an attractive pathway whose inhibition could hamper cytoskeletal compartmentalization and TUBB3 function. [Mol Cancer Ther 2008;7(7):2070–9]

This study investigated the effects of a phytoestrogen-containing standardized soy extract (SSE) on the growth of nonsmall cell lung cancer (NSCLC; A549) xenografts in female athymic mice. Tumor-bearing mice received either sterile water or SSE [50 or 100 mg/(kg x d), per os], 5 d/wk, until the mean tumor weight in each group was at least 900 mg. Treatment with SSE reduced tumor growth in the high-dose group compared with control (P < 0.01); tumors in both treated groups had reduced proliferation and greater apoptosis compared with controls (P < 0.05). SSE treatment also induced diffuse central necrosis, reducing the viable tissue mass within the tumor. Whereas tumor levels of epidermal growth factor receptor were comparable in control and treated mice, the expression of phosphorylated protein kinase B (p-Akt) was lower in tumors of mice treated with 100 mg SSE/(kg x d) than in controls (P < 0.01). The protein level of phosphorylated mitogen-activated protein kinase also tended to be lower (P = 0.07) in this group than in controls. Estrogen receptor (ER)alpha and ERbeta were present in tumors, but their expression levels did not differ among groups. Serum insulin-like growth factor-1 concentrations also were not affected by the treatments. In conclusion, we found that soy phytochemicals slow the in vivo growth of NSCLC xenografts; the modulation of the Akt-signaling pathway observed in tumors of SSE-treated mice may have a role in the activity observed. Our research provides further support for the concept that consumption of phytoestrogens may be effective in delaying lung cancer progression.

Taxanes are presently widely employed for the medical treatment of cancer. However, despite the huge clinical success, these agents exhibit clinical problems related to poor drug solubility, toxicity and, in particular, drug resistance.To identify the critical points related to the process of development of novel taxanes.Publicly available data on the paclitaxel and docetaxel analogues, which have entered a clinical development phase in the last 2 years have been taken into consideration. The development involved novel formulations of paclitaxel and novel chemical entities. For each agent in each category the development phase is analysed and a synthetic comment for each category is included.Despite all the efforts, until now clinical success with the new development of taxanes has been limited. Moreover, the expected clinical introduction of epothilones could further restrict the space for development of novel taxanes. Despite these facts, some interesting concepts emerged during the process of development and could lead to successful drugs in the forthcoming years.