Fatty Acid Modification of the Anticancer Peptide LVTX-9 to Enhance Its Cytotoxicity against Malignant Melanoma Cells

Abstract

Spider venom is a valuable resource for the development of novel anticancer drugs. In this study, we focused on novel linear amphipathic α-helical anticancer peptide LVTX-9, which was derived from the cDNA library of the venom gland of the spider Lycosa vittata. The cytotoxicity of LVTX-9 against murine melanoma cells in the range of 1.56–200 μM was tested and found to be significantly lower than those of most anticancer peptides reported. Its IC50 was determined to be 59.2 ± 19.8 μM in a serum or 76.3 ± 12.7 μM in serum-free medium. Fatty acid modification is a promising strategy for improving peptide performance. Therefore, to enhance the cytotoxic activity of LVTX-9, fatty acid modification of this peptide was performed, and five different carbon chain length lipopeptides named LVTX-9-C12-C20 were produced. Among them, the lipopeptide LVTX-9-C18 showed the highest cytotoxic activity in relation to B16-F10 cells, whether in a serum or serum-free medium. Most importantly, the cytotoxic activity of LVTX-9-C18 was improved by about 12.9 times in a serum medium or 19.3 times in a serum-free medium compared to that of LVTX-9. Subsequently, assays including scanning electron microscopy, trypan blue staining, lactate dehydrogenase leakage assay, and hemolytic activity could indicate that the potential direct cell membrane disruption is the main mechanism of LVTX-9-C18 to induce cancer cell death. Furthermore, the LVTX-9-C18 also showed strong cytotoxicity in relation to 3D B16-F10 spheroids, which indicates it might be a promising lead for developing anticancer drugs.

Emerging cures for cancer: peptides from scorpion and spider venom

“…Another conclusion drawn in the same study showed the anti-proliferation property of LVTX-9-C18 from colonial formation testing [6]. There were three groups of variables: the control group, 10μM of LVTX-9 and 1μM of LVTX-9-C18.…”

“…In a recent study done by Fengjiao Li et al, peptide LVTX-9 from Lycosa vittata was isolated to test its toxicity after modified by fatty acids (octadecanoic acid conjugation) [6]. The five lipopeptides produced had an increasing number of carbon atoms from 12 carbons to 20 carbons and an ascending order of hydrophobicity.…”

“…Among these lipopeptides, LVTX-9-C18 has shown the strongest cytotoxicity in both serum-free and serum-containing conditions, and the cytotoxic ability of LVTX-9-C18 was much higher than the cytotoxic ability shown by LVTX-9 (Figure1). LVTX-9 and five lipopeptides' cytotoxic effects on mouse skin melanoma cells in the media with serum (A) and without serum (B) were assessed using the CCK-8 assay, adapted from ref [6].…”

“…(B) Bar chart presenting the colony formation quantitively. Adapted from ref [6]. Fortunately, it was also shown that LVTX-9-C18 has cytotoxicity to the 3D tumour spheroids based on a cytotoxic assay in vitro [6].…”

“…Adapted from ref [6]. Fortunately, it was also shown that LVTX-9-C18 has cytotoxicity to the 3D tumour spheroids based on a cytotoxic assay in vitro [6]. As a result, researchers conjecture that LVTX-9-C18 has the cytotoxic ability to cancer cells in animals.…”