Ageing is the predominant risk factor for cardiovascular diseases and contributes to a significantly worse outcome in patients with acute myocardial infarction. MicroRNAs (miRNAs) have emerged as crucial regulators of cardiovascular function and some miRNAs have key roles in ageing. We propose that altered expression of miRNAs in the heart during ageing contributes to the age-dependent decline in cardiac function. Here we show that miR-34a is induced in the ageing heart and that in vivo silencing or genetic deletion of miR-34a reduces age-associated cardiomyocyte cell death. Moreover, miR-34a inhibition reduces cell death and fibrosis following acute myocardial infarction and improves recovery of myocardial function. Mechanistically, we identified PNUTS (also known as PPP1R10) as a novel direct miR-34a target, which reduces telomere shortening, DNA damage responses and cardiomyocyte apoptosis, and improves functional recovery after acute myocardial infarction. Together, these results identify age-induced expression of miR-34a and inhibition of its target PNUTS as a key mechanism that regulates cardiac contractile function during ageing and after acute myocardial infarction, by inducing DNA damage responses and telomere attrition.

A case involving a 67 year old man with an immunocytoma initially presenting as Waldenström's macroglobulinemia which transformed into a high grade malignant lymphoma of immunoblastic type after treatment with cyclophosphamide and corticosteroids over 5 months is presented. IgM (kappa) present in the serum in the phase of immunocytoma was demonstrated also on the less differentiated cells of the high grade lymphoma. The permanent production of the same immunoglobulin molecule suggests that both morphologically different malignancies derived from one B cell clone.

Introduction RG7386 is a novel bispecific antibody, binding with high affinity to fibroblast activation protein (FAP) and with low affinity to death receptor 5 (DR5). Avidity-driven binding of the bispecific antibody mediates hyper-clustering of DR5 thus triggering tumor cell death. Induction of FAP dependent apoptosis translated into strong efficacy in vivo using patient derived xenografts thereby proposing RG7386 as an attractive therapeutic approach for the treatment of stroma rich FAP-positive solid tumors as well as FAP positive sarcomas. However, thus far DR5 targeting strategies failed to show clinical efficacy likely due to lack of hyperclustering and intrinsic resistance mechanisms. Preclinical translational studies were conducted to demonstrate the on-target mode of action, to ensure maximal activity and to guide pharmacodynamic (PD) analysis to unravel potential resistance mechanisms. Material and Methods Based on strong anti-tumor efficacy of RG7386 alone and in combination with irinotecan in a colorectal cancer (CRC) cell line based xenograft model (DLD-1) co-injected with fibroblasts a kinetic study was designed. Tumors were explanted 6, 16, 72 and 168 hours after RG7386 single agent treatment and harvested for immunohistochemical (IHC) and ELISA based protein analysis of apoptosis markers, such as cleaved caspase 3 (cc3), cleaved PARP and activated caspase 8 and 9. Additionally, PD effects of RG7386 treatment as single agent and in combination with doxorubicin were investigated in a FAP positive desmoplastic melanoma cell line derived model (LOX-IMVI). Results We observed significant time-dependent induction of apoptosis upon treatment with RG7386 by IHC and ELISA in xenograft tumors expressing FAP in stroma or on tumor cells directly. High, transient levels of apoptosis markers such as cc3 were observed by IHC early after treatment compared to vehicle control. Analysis of equivalent tissue lysates by ELISA revealed also rapid induction of cc3, cleaved PARP and activated caspase 8 and 9 in monotherapy in the DLD-1 CRC xenograft model which was superior when given together with doxorubicin in the LOX-IMVI desmoplastic melanoma model. Conclusion We identified that RG7386 strongly induces tumor cell apoptosis in vivo shortly after injection independently if FAP was expressed on tumor stroma or at tumor cells and discovered optimal pharmacodynamic markers and time points for sampling and analysis. As a result, early clinical trials of RG7386 will be designed to increase the therapeutic potential by choosing the right combination partner and to ensure demonstration of the postulated mode of action by pharmacodynamic data. Citation Format: Thomas Friess, Ann-Marie Broeske, Stefanie Lechner, Esther Abraham, Gabriele Hoelzlwimmer, Hadassa Sade, Peter Bruenker, Oliver Krieter. Preclinical pharmacodynamic biomarker and combination strategy of RG7386, a novel FAP-DR5 bispecific antibody for targeting solid tumors. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C125.

Background: Activation of the extrinsic apoptotic pathway by TRAIL is dependent on clustering of death receptors (DR) on the surface of cells. However, current TRAIL-based strategies have proven ineffective in clustering death receptors and failed to demonstrate robust therapeutic activity in clinical trials. More potent DR agonist therapies could help to overcome insufficient pathway activation and resistance to TRAIL activation. RG7386 is a novel bispecific FAP-DR5 antibody, binding with high affinity to fibroblast activation protein (FAP) and with low affinity to DR5. FAP is expressed at high prevalence on cancer associated fibroblasts (CAFs) in various tumor types as well as on tumors of mesenchymal origin, such as sarcomas. Avidity-driven binding of the bispecific antibody induces hyperclustering of DR5, which leads to potent induction of extrinsic apoptosis pathway signaling and tumor cell death. Biomarkers will be crucial in predicting sensitivity to DR5 activation and apoptosis induction and for selection of patients most likely to benefit from treatment with RG7386. Aim: The aim of the study was to explore the efficacy of RG7386 in vitro and in vivo. CRC and PDAC xenograft models expressing FAP on tumor stroma as well as sarcoma models were used to explore in vivo efficacy. Molecular profiling of sensitive and resistant tumors was also performed to identify response prediction markers. Results: RG7386 demonstrated additive efficacy in vitro with clinically relevant combinations (e.g. irinotecan, paclitaxel) in a variety of CRC and PDAC cell lines. In a xenograft model, where CRC cells (DLD-1) were co-injected with fibroblasts, RG7386 showed strong anti-tumor efficacy in combination with irinotecan. Remarkably, in a patient-derived CRC xenograft model (Co5896), the efficacy of RG7386 in combination with irinotecan induced complete tumor remission in all mice (n = 10/10). Furthermore, the combination of RG7386 with doxorubicin generated complete remissions in FAP+ sarcoma patient and desmoplastic melanoma cell line derived xenograft models such as Sarc4605 and LOX-IMVI. Finally, extensive molecular profiling of sensitive and resistance models in vitro revealed a distinct response prediction signature of DR5 sensitivity. Conclusion: RG7386 is a novel bispecific antibody inducing avidity-driven DR5 crosslinking by binding to FAP. This induces potent apoptosis of tumor cells, making it an attractive therapeutic approach for treatment of FAP+ solid tumors. Encouraging data indicate the high potential of RG7386 to treat FAP positive sarcomas. A comprehensive biomarker program will be employed in the early clinical development of RG7386 to enable selection of patients likely to benefit and to corroborate the mode of action, anti-tumor activity and potential response prediction markers. Citation Format: Thomas Friess, Stefanie Lechner, Esther Abraham, Ann-Marie Broeske, Sabine Bader, Andreas Roller, Meher Majety, Katharina Wartha, Suzana Vega-Harring, Hadassah Sade, Oliver Krieter, Peter Bruenker. Induction of avidity-driven hyperclustering of DR5 by a new FAP-DR5 bispecific antibody (RG7386) leads to strong anti-tumor efficacy. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 952. doi:10.1158/1538-7445.AM2015-952

HER3 is a member of the Human Epidermal Growth Factor Receptor (HER) family. HER3 is a kinase dead receptor, but by forming heterodimers with other HER family receptors, HER3 works as amplifier for PI3 kinase driven tumorigenesis. It has been reported that tumors treated with EGFR-, HER2-, cMET-or mTOR targeted therapies can escape via HER3 activation or upregulation. HER3 is expressed in a large variety of tumors for example in non-small cell lung cancer (NSCLC), head and neck, colorectal, gastric, pancreatic, breast, ovarian, thyroid and prostate cancer. Anti-HER3 antibodies can work via various mechanisms including: (1) blocking ligand (HRGs) binding to the receptor, (2) blocking heterodimerization with other HER family members (HER1, 2 and 4), (3) downregulation of the receptor from the cell surface, and (4) engaging immune effector functions such as antibody-dependent cellular cytotoxicity (ADCC). The first three mechanisms lead to inhibition of HER3 phosphorylation and downstream signaling thereby resulting in tumor cell growth inhibition, while ADCC is a mechanism of direct target cell killing triggered by cross-linking of Fc receptors on immune effector cells (e.g. NK cells, macrophages). RG7116 is a novel humanized and glycoengineered IgG1 antibody currently in clinical development, that binds to HER3 with high affinity. This antibody prevents ligand binding and receptor heterodimerization, thereby blocking receptor phosphorylation. In various tumor xenograft models monotherapy treatment with this antibody leads to substantial tumor growth inhibition. Only in a few cases monotherapy treatment resulted in complete tumor remission. Most of the models initially show convincing efficacy, but tumors regrow after a while. Combination therapy with other HER targeted therapies such as pertuzumab, cetuximab or erlotinib, lead to complete remission in preclinical models. The combination of RG7116 with downstream signaling inhibitors like: everolimus (mTOR) andand other anti-cancer agents leads to increased efficacy. Citation Format: Birgit Bossenmaier, Thomas Friess, Martin Weisser, Stefanie Lechner, Esther Abraham, Monika Hoch, Christian Mirschberger. RG7116, a novel humanized anti-HER3 antibody with superior preclinical in vitro and in vivo efficacy in combination with, everolimus and other anti-cancer agents. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2668. doi:10.1158/1538-7445.AM2014-2668