Remission and tumor cell protection in PVG rats by subcutaneous injection of LTX-315 into an aggressive malignant rat mesenchymal tumor with stemness characteristics.

e21046 Background: LTX-315 (Oncopore) is a chemically designed cationic nonapeptide derived from a natural host defensive CAP, bovine lactoferricin (LfcinB) in development for local treatment of tumours. Earlier studies have demonstrated that treatment of A20 lymphomas and CT26WT carcinomas with LTX-315 in immunocompetent mice resulted in tumour regression. Re-challenge with tumor cells in the cured animals showed that a long- term protection was induced against the tumor. Methods: In the current experiments we have investigated if LTX-315 also can have the same effect on a novel established malignant rat mesenchymal tumor cell line with “stemness” properties. Following long term culturing of bone marrow derived rat mesenchymal cells we developed a rat transformed mesenchymal cell line (rTMSC). Previously we have shown that s.c. as well as i.v. and i.p. injection of rTMSC form immature sarcoma tumors both in nude rats as well as in PVG rats. The rTMSC has been stabled marked with a dual reporter gene GFP ...