Emily Capone

miR-205-5p -mediated downregulation of ErbB/HER receptors in breast cancer stem cells results in targeted therapy resistance

The ErbB tyrosine kinase receptor family has been shown to have an important role in tumorigenesis, and the expression of its receptor members is frequently deregulated in many types of solid tumors. Various drugs targeting these receptors have been approved for cancer treatment. Particularly, in breast cancer, anti-Her2/EGFR molecules represent the standard therapy for Her2-positive malignancies. However, in a number of cases, the tumor relapses or progresses thus suggesting that not all cancer cells have been targeted. One possibility is that a subset of cells capable of regenerating the tumor, such as cancer stem cells (CSCs), may not respond to these therapeutic agents. Accumulating evidences indicate that miR-205-5p is significantly downregulated in breast tumors compared with normal breast tissue and acts as a tumor suppressor directly targeting oncogenes such as Zeb1 and ErbB3. In this study, we report that miR-205-5p is highly expressed in BCSCs and represses directly ERBB2 and indirectly EGFR leading to resistance to targeted therapy. Furthermore, we show that miR-205-5p directly regulates the expression of p63 which is in turn involved in the EGFR expression suggesting a miR-205/p63/EGFR regulation.

EV20-Sap, a novel anti-HER-3 antibody-drug conjugate, displays promising antitumor activity in melanoma

Melanoma is the most biologically aggressive skin cancer of well established constitutive and induced resistance to pharmacological treatment. Despite the recent progresses in immunotherapies, many advanced metastatic melanoma patients still face a significant mortality risk. The aggressive nature of this disease sustains an urgent need for more successful, effective drugs. HER-3 - one of the four member of the tyrosin kinase epidermal growth factor receptors (EGFRs) family- is frequently overexpressed in solid tumors, including melanoma. Moreover, up-regulation of HER-3 and its ligand NRGβ-1 are associated with poor prognosis, thus suggesting this receptor as a suitable target for cancer therapy. Several monoclonal antibodies targeting HER-3 are currently available, but preliminary results from clinical testing of these agents reveal a modest efficacy. Thus, a substantial improvement over this immunotherapeutic approach could be offered by an anti-HER-3 based Antibody-Drug Conjugate (ADC). In the present paper, we describe the generation of an ADC obtained by coupling the HER-3 targeting antibody EV20 linked to the plant toxin Saporin (Sap). In vitro, this ADC displays a powerful, specific and target-dependent cytotoxic activity which correlates with the degree of expression and internalization of HER-3 on tumor cells. Furthermore, in a murine melanoma model, EV20-Sap treatment leads to a significant reduction of the number of pulmonary metastasis.

EV20-mediated delivery of cytotoxic auristatin MMAF exhibits potent therapeutic efficacy in cutaneous melanoma

&NA; Cutaneous melanoma is one of the cancers with the fastest rising incidence and in its advanced metastatic form is a highly lethal disease. Despite the recent approval of several new drugs, the 5‐year overall survival rate for advanced cutaneous melanoma is still below 20% and therefore, the development of novel treatments remains a primary need. Antibody‐Drug Conjugates are an emerging novel class of anticancer agents, whose preclinical and clinical development has recently seen a remarkable increase in different tumors, including melanoma. Here, we have coupled the anti‐HER‐3 internalizing antibody EV20 to the cytotoxic drug monomethyl auristatin F (MMAF) to form a novel antibody‐drug conjugate (EV20/MMAF). In a panel of human melanoma cell lines, this novel ADC shows a powerful, specific and target‐dependent cell killing activity, independently of BRAF status. Efficacy studies demonstrated that a single administration of EV20/MMAF leads to a long‐lasting tumor growth inhibition. Remarkably, the effect of this novel ADC was superior to the BRAF inhibitor vemurafenib in preventing kidney, liver and lung melanoma metastases. Overall, these results highlight EV20/MMAF as a novel ADC with promising therapeutic efficacy, warranting extensive pre‐clinical evaluation in melanoma with high levels of HER‐3 expression.

Generation of a novel Antibody-Drug Conjugate targeting endosialin: potent and durable antitumor response in sarcoma

The endosialin/CD248/TEM1 receptor is expressed on the cell surface of tumor-associated stroma cells as well as in sarcoma and neuroblastoma cells. This receptor is emerging as an attractive molecule in diagnostics and therapeutics because of its expression across the stroma of many human tumors, the low to absent expression in normal tissues and accessibility from the vascular circulation. In this study, we present evidence of the preclinical efficacy of a novel Antibody-Drug Conjugate (ENDOS/ADC). It consists of a humanized endosialin monoclonal antibody, named hMP-E-8.3, conjugated to a potent duocarmycin derivative. In endosialin expressing cancer cell lines, this ENDOS/ADC showed a powerful, specific and target-dependent killing activity. High expression levels of endosialin in cells correlated with efficient internalization and cytotoxic effects in vitro. Efficacy studies demonstrated that ENDOS/ADC treatment led to a long-lasting tumor growth inhibition of a cell line-based model of human osteosarcoma. Taken together, our results demonstrate that endosialin is an attractive target in sarcoma and suggest that ENDOS/ADC has the potential to be developed into a bio-therapeutic agent for these malignancies.The endosialin/CD248/TEM1 receptor is expressed on the cell surface of tumor-associated stroma cells as well as in sarcoma and neuroblastoma cells. This receptor is emerging as an attractive molecule in diagnostics and therapeutics because of its expression across the stroma of many human tumors, the low to absent expression in normal tissues and accessibility from the vascular circulation. In this study, we present evidence of the preclinical efficacy of a novel Antibody-Drug Conjugate (ENDOS/ADC). It consists of a humanized endosialin monoclonal antibody, named hMP-E-8.3, conjugated to a potent duocarmycin derivative. In endosialin expressing cancer cell lines, this ENDOS/ADC showed a powerful, specific and target-dependent killing activity. High expression levels of endosialin in cells correlated with efficient internalization and cytotoxic effects in vitro. Efficacy studies demonstrated that ENDOS/ADC treatment led to a long-lasting tumor growth inhibition of a cell line-based model of human osteosarcoma. Taken together, our results demonstrate that endosialin is an attractive target in sarcoma and suggest that ENDOS/ADC has the potential to be developed into a bio-therapeutic agent for these malignancies.

Abstract 40: Development of a novel antibody-drug conjugate targeting endosialin/TEM-1: potent antitumor activity in sarcoma

The TEM-1/Endosialin/CD248 receptor is expressed in the cell surface of tumor-associated stroma cells, as well as in sarcoma and neuroblastoma cells. This receptor is emerging as an attractive molecule in diagnostics and therapeutics because of its expression across the stroma of many human tumors, the low to absent expression in normal tissues and accessibility from the vascular circulation. In this study, we present evidence of the preclinical efficacy of a novel Antibody-Drug Conjugate (ADC). It consists of a humanized TEM-1 monoclonal antibody (E.8-3) conjugated to a highly potent payload (TEM-1-ADC). In TEM-1 expressing cancer cell lines, this TEM-1-ADC demonstrated a powerful, specific and target-dependent killing activity. High expression levels of TEM-1 in cells correlated with efficient internalization, efficacy, and cytotoxic effects in vitro. Efficacy studies demonstrated that TEM-1-ADC treatment leads to a long lasting tumor growth inhibition of cell line-based models of human sarcoma. Taken together, our results demonstrated that TEM-1 is an attractive target in sarcoma and suggest that TEM-1-ADC has the potential to be developed into a biotherapeutic agent in these malignancies. Citation Format: Gianluca Sala, Stefano Iacobelli, Emily Capone, Enza PIccolo, Jean-Fred Sauniere, Vanessa Vannucci Douet. Development of a novel antibody-drug conjugate targeting endosialin/TEM-1: potent antitumor activity in sarcoma [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 40. doi:10.1158/1538-7445.AM2017-40

Abstract 41: An Antibody Drug Conjugate targeting HER-3 demonstrates promising antitumor efficacy in a wide range of human cancer

The HER-3 receptor is emerging as an attractive molecule in therapeutics because of its overexpression across many human cancers and because of its role in in several compensatory processes that underlay emergence of resistance to certain cancer drugs. In this study, we present evidence of the preclinical efficacy of a novel Antibody-Drug Conjugate (ADC) targeting HER-3. It consists of a humanized HER-3 monoclonal antibody (mAb EV20), which recognizes the HER-3 extracellular domain, conjugated to different payloads (HER-3-ADC)s. In HER-3 expressing cancer cell lines, these HER-3-ADCs demonstrated a powerful, specific and target-dependent killing activity. High expression levels of HER-3 in tumor cells correlated with efficient internalization, efficacy, and cytotoxic effects in vitro. Efficacy studies demonstrated that HER-3-ADCs treatment leads to a long lasting tumor growth inhibition of cell line-based models of human head and neck, breast, pancreatic, prostatic, lung, stomach cancers and melanoma. Overall, these findings validate HER-3 as an attractive therapeutic target in multiple solid tumors and support further clinical development and application of HER-3 targeting ADCs. Citation Format: Gianluca Sala, Manuela Iezzi, Alessia Lamolinara, Emily Capone, Stefano Iacobelli, Jean-Fred Sauniere, Sara Ponziani, Francesco Giansanti, Rodolfo Ippoliti. An Antibody Drug Conjugate targeting HER-3 demonstrates promising antitumor efficacy in a wide range of human cancer [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 41. doi:10.1158/1538-7445.AM2017-41

Abstract 5437: Dual targeting of ErbB-2 and ErbB-3: A new potential strategy for the treatment of pancreatic cancer

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA Background: Pancreatic cancer (PC) is one of the most lethal cancers and there is an urgent need to find out new therapeutic approaches. Deregulated signaling through ErbB-1 and ErbB-2, members of the epidermal growth factor receptor family, frequently occurs in PC. However, attempts aiming at inhibiting ErbB-1 and ErbB-2 have revealed only a modest impact on disease outcome. A growing body of evidence suggests that ErbB-3 and its ligand NRG-1β are key players in driving oncogenic signaling and resistance to targeted therapy in PC. We have recently developed a novel humanized ErbB-3 antibody, named EV20, which displayed a potent antitumor activity by promoting receptor downregulation in vitro and in vivo. Here we hypothesized that targeting of ErbB-3 with EV20 would enhance the therapeutic effect of ErbB-2 inhibitors in PC. Materials and Methods: Three different PC cell lines (BxPC-3, HPAF II and SW1990) were chosen based on their metastatic origin, genetic background (KRAS status) and responsiveness to erlotinib. The expression of ErbB-1, ErbB-2 and ErbB-3 was analyzed by FACS and WB. The effects of trastuzumab, cetuximab, EV20 and their combinations on NRG-1β-induced activation of the ErbB3/PI3K/Akt axis, cell proliferation, and in vivo tumor growth were evaluated by standard procedures. Results: ErbB-1 was overexpressed by all the cell lines, whereas the expression levels of ErbB-2 and ErbB-3 were moderate in HPAFII cells and low in BxPC-3 and SW1990 cells. NRG-1β was more effective than EGF (an ErbB-1 ligand) in activating ErbB-3 downstream signaling, which was not inhibited by cetuximab, despite a high ErbB-1 expression in the cells. Conversely, inhibition of ErbB-2 and/or ErbB-3 resulted in a marked suppression of NRG-1β-driven Akt activation. Finally, EV20 in combination with trastuzumab exerted a superior antitumor activity compared to single agent alone in terms of cell proliferation and growth of PC xenografts in nude mice. Conclusions: Dual targeting of ErbB-2 and ErbB-3 could represent a newer therapeutic approach in PC. Note: This abstract was not presented at the meeting. Citation Format: Gianluca Sala, Reza Ghasemi, Emily Capone, Ilario Giovanni Rapposelli, Sara Traini, Cosmo Rossi, Pier Giorgio Natali, Stefano Iacobelli. Dual targeting of ErbB-2 and ErbB-3: A new potential strategy for the treatment of pancreatic cancer. [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 5437. doi:10.1158/1538-7445.AM2014-5437