Oncolytic immunotherapies represent a new promising strategy in the treatment of cancer. In our efforts to develop oncolytic peptides, we identified a series of chemically modified 9-mer cationic peptides that were highly effective against both drug-resistant and drug-sensitive cancer cells and with lower toxicity toward normal cells. Among these peptides, LTX-315 displayed superior anticancer activity and was selected as a lead candidate. This peptide showed relative high plasma protein binding abilities and a human plasma half-life of 160 min, resulting in formation of nontoxic metabolites. In addition, the lead candidate demonstrated relatively low ability to inhibit CYP450 enzymes. Collectively these data indicated that this peptide has potential to be developed as a new anticancer agent for intratumoral administration and is currently being evaluated in a phase I/IIa study.

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Five new triterpene saponins, 3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-d-glucuronopyranosyl-22-O-beta,beta-dimethylacryloyl-A1-barrigenol (1), 3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-d-glucuronopyranosyl-22-O-angeloyl-R1-barrigenol (2), 3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-d-glucuronopyranosyl-21-O-acetyl-22-O-angeloyl-R1-barrigenol (3), 3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-d-glucuronopyranosyl-21-O-acetyl-22-O-beta,beta-dimethylacryloyl-R1-barrigenol (4), and 3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-d-glucuronopyranosyl-22-O-angeloyl-28-O-acetyl-R1-barrigenol (5), were isolated from the roots of Eryngium campestre. Their structures were established mainly by 2D NMR techniques and mass spectrometry. Compounds 1-4 and 3-O-beta-d-glucopyranosyl-(1-->2)-[alpha-l-rhamnopyranosyl-(1-->4)]-beta-d-glucuronopyranosyl-22-O-beta,beta-dimethylacryloyl-A1-barrigenol, previously isolated from the same plant, showed a weak cytotoxicity when tested against HCT 116 and HT 29 human colon cancer cells.

Chemokines and their receptors play important roles in various aspects of tumoral processes, and evidence was provided for their critical involvement in determining the metastatic destination of tumor cells. Here, we analyzed in vitro and in vivo, how CCR6 expression could alter the behavior of Lewis lung carcinoma (LLC) cells, which were shown to express low levels of the CCR6 ligand, CCL20 (LARC), both in vitro and in vivo. The expression of CCR6 significantly decreased the number of metastases in immunocompetent C57BL/6 mice, without affecting the tumor-forming ability of LLC cells. This was correlated with a decrease in clonogenicity in soft and hard agar, and with increased adhesion to type-IV collagen. These two observations made in basal conditions were enhanced when CCL20 was added to the assay medium. Thus, expression of CCR6 in tumor cells, associated with the local production of CCL20, decreased the metastatic potential of the LLC line. We propose a model, in which the expression of a chemokine receptor in tumor cells can act as a metastasis-suppressor, or a metastasis-promoting factor, according to the expression, or the absence of expression of the cognate ligand(s) in the tumor.