ytox

Ytox is a naturally occurring cytotoxic peptide first isolated from the oleaginous yeast Yarrowia lipolytica. The peptide, named Ytox for its Yarrowia origin, has a molecular weight of approximately 1,200 daltons and exhibits a fibrin-like secondary structure. Biochemical analysis indicates that Ytox interacts preferentially with phosphatidylserine residues on tumor cell membranes, leading to selective disruption of the plasma membrane and rapid cell death.

The peptide was discovered during a 2012 high‑throughput screening of industrial yeasts for antimicrobial activity. Subsequent assays identified Ytox as the compound responsible for the strong lytic effect observed in several tumor cell lines, including glioblastoma, pancreatic adenocarcinoma, and melanoma. Sequence comparison revealed that Ytox shares limited homology with known antimicrobial peptides, suggesting a novel mechanism of action.

Preclinical studies have explored Ytox as a potential anticancer agent. In vitro experiments demonstrate that Ytox induces dose‑dependent cytotoxicity with an IC50 in the low micromolar range. Mouse xenograft models of human breast cancer administered intraperitoneally with Ytox at 5 mg/kg exhibited significant tumor regression, with minimal weight loss or observable organ toxicity. The peptide’s rapid clearance and lack of long‑term adverse effects in rodents support its further development.

Regulatory assessment of Ytox is ongoing. The compound entered Phase I clinical evaluation in late 2024, focusing on safety, tolerability, and pharmacokinetics in healthy volunteers. Early results indicate that Ytox is well tolerated at doses up to 10 mg/kg, with transient local reactions at the injection site. Regulatory authorities have granted a conditional marketing authorization pathway pending the outcome of Phase II efficacy trials, which are scheduled to commence in 2026.

Future research aims to elucidate the precise molecular interactions of Ytox with lipid membranes and to engineer peptide analogues with enhanced selectivity and reduced immunogenicity. If successful, Ytox could become a new class of targeted anticancer therapeutics, complementing existing modalities such as chemotherapy and immunotherapy.