Biology subjects

Murer, P.

Publications and source records attributed to Murer, P..

3 recordsLinked to original sources

bioRxiv2020

Antibody-mediated delivery of LIGHT to the tumor boosts Natural Killer cells and delays tumor progression

BackgroundLIGHT is a member of the TNF superfamily, which has been claimed to mediate anti-tumor activity on the basis of cancer cures observed in immunocompetent mice bearing transgenic LIGHT-expressing tumors. The preclinical development of a LIGHT-based therapeutic has been hindered by the lack of functional stability exhibited by this protein. MethodsHere, we describe the cloning, expression and characterization of five antibody-LIGHT fusion proteins, directed against the alternatively-spliced EDA domain of fibronectin, a conserved tumor-associated antigen. ResultsAmong the five tested formats, only the sequential fusion of the F8 antibody in single-chain diabody format, followed by the LIGHT homotrimer expressed as a single polypeptide, yielded a protein (termed "F8-LIGHT") which was not prone to aggregation. A quantitative biodistribution analysis in tumor bearing mice, using radioiodinated protein preparations, confirmed that F8-LIGHT was able to preferentially accumulate at the tumor site, with a tumor-to-blood ratio of ca. five to one twenty-four hours after intravenous administration. Tumor therapy experiments, performed in two murine tumor models (CT26 and WEHI-164), featuring different levels of lymphocyte infiltration into the neoplastic mass, revealed that F8-LiGHT could significantly reduce tumor cell growth and was more potent than a similar fusion protein (KSF-LIGHT), directed against hen egg lysozyme and serving as negative control of irrelevant specificity in the mouse. At a mechanistic level, the activity of F8-LiGHT was mainly due to an intratumoral expansion of Natural Killer cells, whereas there was no evidence of expansion of CD8+ T cells, neither in the tumor, nor in draining lymph nodes. ConclusionWe developed a novel recombinant LIGHT fusion protein, able to accumulate at the site of disease and which displayed anti-tumor activity in two mouse models of cancer.

immunology↗

bioRxiv2019

A novel human monoclonal antibody specific to the A33 glycoprotein recognizes colorectal cancer and inhibits metastasis

Colorectal cancer represents the second most common cause of cancer-related death. The human A33 transmembrane glycoprotein is a validated tumor-associated antigen, expressed in 95% of primary and metastatic colorectal cancers. Using phage display technology, we generated a human monoclonal antibody (termed A2) specific to A33 and we compared its epitope and performance to those of previously described clinical-stage anti-human A33 antibodies. All antibodies recognized a similar immunodominant epitope, located in the V-domain of A33, as revealed by SPOT-analysis. The A2 antibody homogenously stained samples of poorly, moderately and well-differentiated colon adenocarcinomas. All antibodies also exhibited an intense staining of healthy human colon sections. The A2 antibody, reformatted in murine IgG2a format, preferentially localized to A33-transfected CT26 murine colon adenocarcinomas in immunocompetent mice with a homogenous distribution within the tumor mass, while other antibodies exhibited a patchy uptake in neoplastic lesions. A2 efficiently induced killing of A33-expressing cells through antibody-dependent cell-mediated cytotoxicity in vitro and was able to inhibit the growth of A33-positive murine CT26 and C51 lung metastases in vivo. Anti-A33 antibodies may thus represent useful vehicles for the selective delivery of bioactive payloads to colorectal cancer, or may be used in IgG format in settings of minimal residual disease.

pharmacology and toxicology↗

bioRxiv2019

The antibody-based delivery of interleukin-12 to solid tumors boosts NK and CD8+ T cell activity and synergizes with immune check-point inhibitors

We describe the cloning and characterization of a novel fusion protein (termed L19-mIL12), consisting of murine interleukin-12 in single-chain format, sequentially fused to the L19 anti-body in tandem diabody format. The fusion protein bound avidly to the cognate antigen (the alternatively-spliced EDB domain of fibronectin), retained the activity of the parental cyto-kine and was able to selectively localize to murine tumors in vivo, as shown by quantitative biodistribution analysis. L19-mIL12 exhibited a potent anti-tumor activity in immunocompetent mice bearing CT26 carcinomas and WEHI-164 sarcomas, which could be boosted by combination with check-point blockade, leading to durable cancer eradication. L19-mIL12 also inhibited tumor growth in mice with Lewis lung carcinoma (LLC), but in this case cancer cures could not be obtained, both in monotherapy and in combination. A microscopic analysis and a depletion experiment of tumor-infiltrating leukocytes illustrated the contribution of NK cells and CD8+ T cells for the anti-cancer activity observed in both tumor models. Upon L19-mIL12 treatment, the density of regulatory T cells (Tregs) was strongly increased in LLC, but not in CT26 tumors. A FACS analysis also revealed that the majority of CD8+ T cells in CT26 tumors were specific to the retroviral AH1 antigen.\n\nNOVELTY AND IMPACT STATEMENTIn this study, we describe the generation of a novel fusion protein consisting of murine inter-leukin-12 fused to the L19 antibody (specific to the EDB domain of fibronectin). L19-mIL12 revealed favourable tumor to organ ratios 24h after intravenous administration and it was able to cure 60% of CT26 tumor-bearing mice. From a clinical perspective, the rapid clearance from circulation should ease the administration to patients as infusions could be stopped upon onset of side-effects.

cancer biology↗