Antibody therapy to human L1CAM in a transgenic mouse model blocks local tumor growth but induces EMT

Abstract

L1 cell adhesion molecule (L1CAM) is overexpressed in many human cancers, confers bad prognosis and augments cell motility, invasion and metastasis. Results from xenograft mouse models suggested that L1CAM antibodies might be promising tools for cancer therapy. Here, we generated human L1CAM-transgenic mice to study therapeutic efficacy and putative side effects in a model system. We established three transgenic lines (M2, M3 and F4) expressing the human L1CAM transgene in brain, kidney and colon with decreasing intensity (M2, M3 > F4). The expression pattern was similar to that of L1CAM in humans. No interference of the transgene with the expression of endogenous L1CAM was observed. Immunohistochemical analysis revealed correct expression of the transgene in mouse cortex and collective duct of the kidney. Injection of 125 Ilabeled L1CAM antibodies resulted in specific enrichment in the kidney but not in the brain. The injection of the therapeutic anti-human L1CAM mAb L1-9.3/2a into transgenic mice even at high doses did not cause behavioral changes or other side effects. Similar results were obtained using a mouse specific L1CAM mAb in normal mice. Tumor therapy experiments were performed using syngeneic mouse tumor cells (RET melanoma and Panc02 pancreatic adenocarcinoma) transduced with human L1CAM. MAb L1-9.3/2a efficiently and specifically attenuated local tumor growth in both model systems without apparent side effects. The therapeutic effect was dependent on immune effector mechanisms. Analysis of Panc02-huL1CAM tumors after therapy showed elevated levels of EGF and evidence of immune-induced epithelial-mesenchymal transition. The results suggest that our transgenic mice are valuable tools to study L1CAM-based antibody therapy.The L1 cell adhesion molecule (L1CAM) is a 200-220 kDa transmembrane glycoprotein of the immunoglobulin (Ig) superfamily composed of six Ig-like domains and five fibronectin Type III repeats followed by a transmembrane region and a highly conserved cytoplasmic tail. 1 L1CAM can interact with itself (homophilic) and with heterophilic ligands such as integrins, CD24, neurocan, neuropilin-1 (NRP-1) and other members of the neural cell adhesion family. Cumulative evidence indicates that L1CAM (CD171) is ectopically expressed at high levels in a variety of cancers, including pancreatic, colorectal, ovarian and endometrial cancers, melanoma and neuroblastoma.2-6 Furthermore, high levels of L1CAM were found associated with increased grade of malignancy, 5,6 epithelial-mesenchymal transition (EMT), 6 poor patient prognosis 5,7,8 and worse response to chemotherapy. 4,7These findings prompted extensive research towards development and preclinical testing of L1CAM specific mAbs for selective targeting of cancers. In line with the role of this molecule in cell motility, invasion and tumorigenesis, [9][10][11] L1CAM-specific mAbs were shown to suppress tumor cell outgrowth and metastasis in xenograft models. [12][13][14] The in vivo action of these mAbs was shown to depend on a combination of im...

A novel method for measuring cellular antibody uptake using imaging flow cytometry reveals distinct uptake rates for two different monoclonal antibodies targeting L1

“…Antibodies which are retained at the cell surface are better suited for immunemediated tumor targeting while antibodies with high internalization rates are the first choice when it comes to drug-delivery to the tumor cells. Based on the findings presented in this publication it is standing to reason to use L1-9.3 for ADCC dependent tumor therapy, which indeed has been done recently (Doberstein et al, 2014;Wolterink et al, 2010), while further developing L1-OV52.24 as a drug-carrier.…”

Quercetin and doxorubicin co-encapsulated biotin receptor-targeting nanoparticles for minimizing drug resistance in breast cancer

“…Firstly, NPs allow higher tumor accumulation of encapsulated drugs by the enhanced permeability and retention (EPR) effect [28]. Secondly, NPs may further increase the tumor-targeted delivery by modification of the surface of NPs with specific tumor cell targeting ligands, such as folic acid, biotin, and antibodies [29–32]. Additionally, NPs can deliver multiple types of agents with different anticancer mechanisms such as a chemotherapeutic drug with a chemosensitizer, to exert synergistic anticancer effects [33–36].…”

Expression of neural cell adhesion molecule L1 (CD171) in neuroectodermal and other tumors: An immunohistochemical study of 5155 tumors and critical evaluation of CD171 prognostic value in gastrointestinal stromal tumors

“…[16–19] In addition, there has been growing interest in targeting this cell membrane molecule on neoplastic cells by chimeric antigen receptor redirected T lymphocytes or specific antibodies. [20–25] However, immunohistochemical data on CD171 expression in germ cell, rare gastrointesitinal and peripheral mesenchymal tumors as well as lymphohematopoietic tumors remains incomplete. Moreover, conflicting data regarding CD171 expression and its prognostic value were reported in renal cell cancers (RCCs) [26–28] and gastrointestinal stromal tumors (GISTs).…”