Table 1.
ACPs showing antitumor and/or antiviral effects, classified according to their structural characteristics into four categories: α-helical, β-pleated sheets, random coil and cyclic [116,117].
| Category | Feature | ACP | Model |
|---|---|---|---|
| α-Helical [118,119,120,121] |
Peptides short in length Simple in structure |
Magainin II | Lung cancer cells (A549) |
| Aurein | Glioblastoma cells (T98G) |
||
| L-K6 | Breast cancer cells (MCF-7) |
||
| LL37 | Colorectal cancer cells (HCT116) | ||
| FK-16 | |||
| β-Pleated sheet [122,123,124,125,126] |
Two or more disulfide bonds Good stability Structures more complex than α-helical |
Bovine lactoferrin (LfcinB) | Gastric cancer cells (MGC803) |
| MPLfcinB6 | Human T leukemia cells | ||
| MPLfcin-P13 | Hepatocellular carcinoma cells (HepG2) | ||
| Human neutrophil peptide (HNP-1) |
Prostate cancer cells (PC-3) |
||
| Random coil ACPs [127,128,129,130,131] |
Rich in proline and glycine Lack of a typical secondary structure |
Alloferon | Herpes simplex virus Human papillomavirus |
| KW-WK | N.R. | ||
| PR39 | N.R. | ||
| PR35 | N.R. | ||
| Cyclic ACPs [132,133,134] |
Closed peptides composed of a head-to-tail cyclization backbone or disulfide bonds that form cystine knots More stable than linear structures |
Hedyotis diffusa Cytide 1–3 | Prostate cancer cells (PC3, DU145, LNCap) |
| H-10 | Malignant melanoma cells (B16) | ||
| RA-XII | Colorectal tumor cells (HCT116) |
N.R. = not reported.