Peptide name : LyeTx-I-b

Source/Organism : Synthetic

Linear/Cyclic : Linear

Chirality : L

Peptide length: 24

C-terminal modification: Linear

N-terminal modification : Amidated

Non-natural peptide information:

Assay type : MTT assay

Assay time : 48-h

Activity : IC50 = 2.47 µM

Cell line : MDA-MB-231

Cancer type : Breast Cancer

Other activity : Antimicrobial

Amino acid composition bar chart :

Molecular mass : 2696.3225 Dalton

Aliphatic index : 1.425

Instability index : 14.9125

Hydrophobicity (GRAVY) : 0.2875

Isoelectric point : 10.602

Charge (pH 7) : 4.7551

Aromaticity : 8.333

Molar extinction coefficient (cysteine, cystine): (0, 0)

Hydrophobic/hydrophilic ratio : 1.6667

hydrophobic moment : -0.594

Missing amino acid : C,D,E,H,M,P,R,S,V,Y

Most occurring amino acid : L

Most occurring amino acid frequency : 7

Least occurring amino acid : I

Least occurring amino acid frequency : 1

Secondary structure fraction (Helix, Turn, Sheet): (62., 12., 45.)

SMILES Notation: CC[C@H](C)[C@H](N)C(=O)N[C@@H](Cc1c[nH]c2ccccc12)C(=O)N[C@@H](CC(C)C)C(=O)N[C@H](C(=O)N[C@@H](C)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](Cc1ccccc1)C(=O)N[C@@H](CC(C)C)C(=O)NCC(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CC(N)=O)C(=O)N[C@@H](CC(C)C)C(=O)NCC(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](C)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CCC(N)=O)C(=O)N[C@@H](CCC(N)=O)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](C)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CC(C)C)C(=O)O)[C@@H](C)O

1 : de Avelar Júnior JT, et al. LyeTxI-b, a Synthetic Peptide Derived From a Spider Venom, Is Highly Active in Triple-Negative Breast Cancer Cells and Acts Synergistically With Cisplatin. Front Mol Biosci. 2022; 9:876833. doi: 10.3389/fmolb.2022.876833

Paper title : LyeTxI-b, a Synthetic Peptide Derived From a Spider Venom, Is Highly Active in Triple-Negative Breast Cancer Cells and Acts Synergistically With Cisplatin.

Doi : https://doi.org/10.3389/fmolb.2022.876833

Abstract : Breast cancer is the most common cancer that affects women globally and is among the leading cause of women's death. Triple-negative breast cancer is more difficult to treat because hormone therapy is not available for this subset of cancer. The well-established therapy against triple-negative breast cancer is mainly based on surgery, chemotherapy, and immunotherapy. Among the drugs used in the therapy are cisplatin and carboplatin. However, they cause severe toxicity to the kidneys and brain and cause nausea. Therefore, it is urgent to propose new chemotherapy techniques that provide new treatment options to patients affected by this disease. Nowadays, peptide drugs are emerging as a class of promising new anticancer agents due to their lytic nature and, apparently, a minor drug resistance compared to other conventional drugs (reviewed in Jafari et al., 2022). We have recently reported the cytotoxic effect of the antimicrobial peptide LyeTx I-b against glioblastoma cells (Abdel-Salam et al., 2019). In this research, we demonstrated the cytotoxic effect of the peptide LyeTx I-b, alone and combined with cisplatin, against triple-negative cell lines (MDA-MD-231). LyeTx-I-b showed a selectivity index 70-fold higher than cisplatin. The peptide:cisplatin combination (P:C) 1:1 presented a synergistic effect on the cell death and a selective index value 16 times greater than the cisplatin alone treatment. Therefore, an equi-effective reduction of cisplatin can be reached in the presence of LyeTx I-b. Cells treated with P:C combinations were arrested in the G2/M cell cycle phase and showed positive staining for acridine orange, which was inhibited by bafilomycin A1, indicating autophagic cell death (ACD) as a probable cell death mechanism. Furthermore, Western blot experiments indicated a decrease in P21 expression and AKT phosphorylation. The decrease in AKT phosphorylation is indicative of ACD. However, other studies are still necessary to better elucidate the pathways involved in the cell death mechanism induced by the peptide and the drug combinations. These findings confirmed that the peptide LyeTx I-b seems to be a good candidate for combined chemotherapy to treat breast cancer. In addition, in vivo studies are essential to validate the use of LyeTx I-b as a therapeutic drug candidate, alone and/or combined with cisplatin.