Evaluation of the biotechnological potential of peptide Cupiennin 1a and analogs

Abstract

Antimicrobial peptides (AMPs) are components in the innate immune system of various organisms, and many AMPs can be found in poisons from animals such as spiders, scorpions, and snakes. The peptide Cupiennin-1a is present in the venom of the spider Cupiennius salei and belongs to a group of peptides called cupiennins. The peptide demonstrated high cytotoxic activity against mammalian cells; thus, aiming to solve this problem, seven analogs were designed (R1a, R1b, R2b, R3b, R6b, R8b, and R10b) based on the primary structure of the peptide Cupiennin 1a, reducing its size and substituting some amino acid residues. The antimicrobial results showed that all Cupiennin 1a analogs displayed antimicrobial activity against the tested bacterial and fungal strains. Cytotoxicity tests demonstrated a decrease in the cytotoxic effect of the analogs when compared to the peptide Cupiennin-1a. The antitumor activity against breast adenocarcinoma lines was observed for all the peptides, displaying a better effect against the MCF-7 and MDAMB-231 cell lines. The eight peptides have insecticidal potential, and the original peptide and analogs R6b, R8b, and R10b showed better efficiency even at low concentrations. The rational design of the analogs led to new molecules displaying activities against different cell types and reduced cytotoxicity toward healthy mammalian cells when compared to the original peptide, demonstrating that this was an interesting approach for the development of molecules with biotechnological potential.

Keywords: analogs; antimicrobial peptides; cytotoxicity; rational design; spider.

Figure 1

Helical wheel projection of analogous synthetic peptides designed based on the Cu-1a peptide sequence. In red, the basic polar amino acid residues; in blue, the acid polar amino acids; in green, the uncharged polar amino acids; and in yellow, the nonpolar amino acids. (A) Cu-1a; (B) R1a; (C) R1b; (D) R2b; (E) R3b; (F) R6b; (G) R8b; and (H) R10b.

Figure 2

Percentage of cell viability in RAW 264.7 cells. (A) Cu-1a; (B) R1a; (C) R1b; (D) R2b; (E) R3b; (F) R6b; (G) R8b; and (H) R10b. One-way ANOVA—Bonferroni’s multiple comparisons test. Each bar represents the mean ± SD of cellular absorbance; N = 3. ^*p < 0.05, ^**p < 0.01, ^***p < 0.001, ^****p < 0.0001, and NS p > 0.05.

Figure 3

Percentage of Cell Viability in HFib cells. (A) R1a; (B) R1b; (C) R2b; (D) R3b; (E) R6b; (F) R8b; and (G) R10b. One-way ANOVA—Bonferroni’s multiple comparisons test. Each bar represents the mean ± SD of cellular absorbance; N = 3. ^*p < 0.05, ^**p < 0.01, ^***p < 0.001, ^****p < 0.0001, and NS p > 0.05.

Figure 4

Percentage of cell viability in MCF-7 cancer cells. (A) Cu-1a; (B) R1a; (C) R1b; (D) R2b; (E) R3b; (F) R6b; (G) R8b; and (H) R10b. One-way ANOVA—Bonferroni’s multiple comparisons test. Each bar represents the mean ± SD of cellular absorbance; N = 3. ^*p < 0.05, ^**p < 0.01, ^***p < 0.001, ^****p < 0.0001, and NS p > 0.05.

Figure 5

Percentage of Cell Viability in MDA-MB231 cancer cells. (A) Cu-1a; (B) R1a; (C) R1b; (D) R2b; (E) R3b; (F) R6b; (G) R8b; and (H) R10b. One-way ANOVA—Bonferroni’s multiple comparisons test. Each bar represents the mean ± SD of cellular absorbance; N = 3. ^*p < 0.05, ^**p < 0.01, ^***p < 0.001, ^****p < 0.0001, and NS p > 0.05.

Figure 6

Cell viability of synthetic peptides tested against SF21 cell line at concentrations of 10, 5, and 1 μM. (A) Cu-1a; (B) R1a; (C) R1b; (D) R2b; (E) R3b; (F) R6b; (G) R8b; and (H) R10b. One-way ANOVA—Bonferroni’s multiple comparisons test. Each bar represents the mean ± SD of cellular absorbance; N = 3. ^*p < 0.05, ^**p < 0.01, ^***p < 0.001, ^****p < 0.0001, and NS p > 0.05.