Entolimod

Abstract: Uveal melanoma (UM) is the most common primary cancer of the eye in adults and progresses to metastatic disease predominantly of the liver in ~50% of patients. In these cases, life expectancy averages just 9 months due to the lack of effective treatment options. The Toll-like receptor 5 (TLR5) agonist entolimod (former name CBLB502) rapidly activates TLR5-NF-κB signaling in hepatocytes and suppresses growth of both TLR5-expressing and non-expressing tumors in the liver through mobilization and activation of innate and adaptive immune mechanisms. The goal of this study was to explore the potential of entolimod as an immunotherapeutic agent against hepatic metastasis of UM using the TLR5-positive B16LS9 mouse model of ocular melanoma. Mice were given seven subcutaneous injections of vehicle or entolimod given 72 h apart started one day before, on the same day or three days after intraocular injection of B16LS9 cells. All tested regimens of entolimod treatment resulted in significantly reduced B16LS9 metastasis to the liver. Entolimod induced mobilization of natural killer (NK) cells to the liver and stimulated their maturation, differentiation and activation. Antibody-mediated depletion of NK cells from mice abrogated entolimod's antimetastatic activity in the liver and eliminated the entolimod-elicited in vitro cytotoxic activity of hepatic lymphocytes against B16LS9 cells. These results provide pre-clinical evidence of entolimod's efficacy against hepatometastasis of UM and support its further development as an anticancer immunotherapeutic drug.

Abstract: Radiation treatment of head and neck cancer frequently causes severe collateral damage to normal tissues including mouth mucosa, salivary glands and skin. This toxicity limits the radiation dose that can be delivered and affects the patient's quality of life. Previous studies in mice and nonhuman primates showed that entolimod, a toll-like receptor 5 (TLR5) agonist derived from bacterial flagellin, effectively reduced radiation damage to hematopoietic and gastrointestinal tissues in both total-body and local irradiation scenarios, with no protection of tumors. Here, using a mouse model, we analyzed the efficacy of entolimod administered before or after irradiation in reducing damage to normal tissues. Animals received local fractionated radiation to the head and neck area, thus modeling radiotherapy of head and neck cancer. Tissue damage was evaluated through histomorphological examination of samples collected at different time points up to four weeks, mice were exposed locally to five daily fractions of ...

Abstract: // Bojidar M. Kojouharov 1 , Craig M. Brackett 1 , Jean M. Veith 1 , Christopher P. Johnson 1 , Ilya I. Gitlin 1 , Ilia A. Toshkov 2 , Anatoli S. Gleiberman 2 , Andrei V. Gudkov 1,2,3 and Lyudmila G. Burdelya 1,2 1 Department of Cell Stress Biology, Roswell Park Cancer Institute, Buffalo, NY 2 Buffalo BioLabs, LLC, Buffalo, NY 3 Cleveland BioLabs, Inc., Buffalo, NY Correspondence: Lyudmila Burdelya, email: // Keywords : TLR5, flagellin, chemotherapy, hematopoietic, gastrointestinal toxicity, tumor Received : January 27, 2014 Accepted : February 23, 2014 Published : February 23, 2014 Abstract Myelosuppression and gastrointestinal damage are common side effects of cancer treatment limiting efficacy of DNA-damaging chemotherapeutic drugs. The Toll-like receptor 5 (TLR5) agonist Entolimod has demonstrated efficacy in mitigating damage to hematopoietic and gastrointestinal tissues caused by radiation. Here, using 5-Fluorouracil (5-FU) treated mice as a model of chemotherapy-induced side effects, we demonstrated significant reduction in the severity of 5-FU-induced morbidity and increased survival accompanied by the improved integrity of intestinal tissue and stimulated the restoration of hematopoiesis. Entolimod-stimulated IL-6 production was essential for Entolimod’s ability to rescue mice from death caused by doses of 5-FU associated with hematopoietic failure. In contrast, IL-6 induction was not necessary for protection and restoration of drug-damaged gastrointestinal tissue by Entolimod. In a syngeneic mouse CT26 colon adenocarcinoma model, Entolimod reduced the systemic toxicity of 5-FU, but did not reduce its antitumor efficacy indicating that the protective effect of Entolimod was selective for normal, non-tumor, tissues. These results suggest that Entolimod has clinical potential to broaden the therapeutic window of genotoxic anticancer drugs by reducing their associated hematopoietic and gastrointestinal toxicities.

Abstract: Tumor necrosis factor alpha (TNF) is capable of inducing regression of solid tumors. However, TNF released in response to Toll-like receptor 4 (TLR4) activation by bacterial lipopolysaccharide (LPS) is the key mediator of cytokine storm and septic shock that can cause severe tissue damage limiting anticancer applications of this cytokine. In our previous studies, we demonstrated that activation of another Toll-like receptor, TLR5, could protect from tissue damage caused by a variety of stresses including radiation, chemotherapy, Fas-activating antibody and ischemia-reperfusion. In this study, we tested whether entolimod could counteract TNF-induced toxicity in mouse models. We found that entolimod pretreatment effectively protects livers and lungs from LPS- and TNF-induced toxicity and prevents mortality caused by combining either of these agents with the sensitizer, D-galactosamine. While LPS and TNF induced significant activation of apoptotic caspase 3/7, lipid tissue peroxidation and serum ALT accumulation in mice without entolimod treatment, these indicators of toxicity were reduced by entolimod pretreatment to the levels of untreated control mice. Entolimod was effective when injected 0.5–48 hours prior to, but not when injected simultaneously or after LPS or TNF. Using chimeric mice with hematopoiesis differing in its TLR5 status from the rest of tissues, we showed that this protective activity was dependent on TLR5 expression by non-hematopoietic cells. Gene expression analysis identified multiple genes upregulated by entolimod in the liver and cultured hepatocytes as possible mediators of its protective activity. Entolimod did not interfere with the antitumor activity of TNF in mouse hepatocellular and colorectal tumor models. These results support further development of TLR5 agonists to increase tissue resistance to cytotoxic cytokines, reduce the risk of septic shock and enable safe systemic application of TNF as an anticancer therapy.