lactoferricin-b and Breast-Neoplasms

The effect on the cytotoxicity against breast cancer cell lines of the substitution of

Topics: Animals; Anti-Bacterial Agents; Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cattle; Cell Proliferation; Female; Humans; Lactoferrin; Peptide Fragments; Tumor Cells, Cultured

Linear, dimeric, tetrameric, and cyclic peptides derived from lactoferricin B, containing the RRWQWR motif, were designed, synthesized, purified, and characterized using RP-HPLC chromatography and MALDI-TOF mass spectrometry. The antibacterial activity of the designed peptides against

Topics: Amino Acid Sequence; Animals; Anti-Bacterial Agents; Antineoplastic Agents; Apoptosis; Bacteria; Breast Neoplasms; Cattle; Cell Line, Tumor; Cell Proliferation; Chromatography, High Pressure Liquid; Dose-Response Relationship, Drug; Female; Humans; Lactoferrin; Mass Spectrometry; Peptides

Lactoferrin (LF) is a mammalian host defense glycoprotein with diverse biological activities. Peptides derived from the cationic region of LF possess cytotoxic activity against cancer cells in vitro and in vivo. Bovine lactoferricin (LFcinB), a peptide derived from bovine LF (bLF), exhibits broad-spectrum anticancer activity, while a similar peptide derived from human LF (hLF) is not as active. In this work, several peptides derived from the N-terminal regions of bLF and hLF were studied for their anticancer activities against leukemia and breast-cancer cells, as well as normal peripheral blood mononuclear cells. The cyclized LFcinB-CLICK peptide, which possesses a stable triazole linkage, showed improved anticancer activity, while short peptides hLF11 and bLF10 were not cytotoxic to cancer cells. Interestingly, hLF11 can act as a cell-penetrating peptide; when combined with the antimicrobial core sequence of LFcinB (RRWQWR) through either a Pro or Gly-Gly linker, toxicity to Jurkat cells increased. Together, our work extends the library of LF-derived peptides tested for anticancer activity, and identified new chimeric peptides with high cytotoxicity towards cancerous cells. Additionally, these results support the notion that short cell-penetrating peptides and antimicrobial peptides can be combined to create new adducts with increased potency.

Topics: Animals; Anti-Infective Agents; Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cattle; Female; Hemolysis; Humans; Jurkat Cells; Lactoferrin; Peptide Fragments; Tumor Cells, Cultured

Bovine lactoferricin (LfcinB) is a cationic antimicrobial peptide with potent cytotoxic activity against cancer cells. The antimicrobial activity of LfcinB resides in its RRWQWR amino acid sequence (referred to here as LfcinB6); however, the anticancer activity of LfcinB6 is not known. Here, we show that free LfcinB6 did not kill T-leukemia or breast cancer cells but LfcinB6 was strongly cytotoxic when delivered to the cytosolic compartment by fusogenic liposomes. LfcinB6 bound weakly to isolated mitochondria but, unlike LfcinB, did not permeabilize mitochondria or cause cytochrome c to be released. Cathepsin B and caspase activity were important for cytotoxicity caused by intracellular LfcinB6 whereas reactive oxygen species were not involved. The mechanism of LfcinB6-induced cytotoxicity is therefore different from that of LfcinB. We suggest that LfcinB6, in combination with a fusogenic liposome delivery system that selectively targets malignant cells, has potential as a novel anticancer agent.

Topics: Amino Acid Sequence; Animals; Antimicrobial Cationic Peptides; Antineoplastic Agents; Breast Neoplasms; Cattle; Drug Delivery Systems; Humans; Jurkat Cells; Lactoferrin; Leukemia, T-Cell; Liposomes

Bovine lactoferricin (LfcinB) is a cationic peptide that selectively induces caspase-dependent apoptosis in human leukemia and carcinoma cell lines. Ceramide is a second messenger in apoptosis signaling that has been shown to increase the cytotoxicity of various anti-cancer drugs. In this study, we determined whether manipulation of intracellular ceramide levels enhanced LfcinB-induced apoptosis of estrogen-nonresponsive MDA-MB-435 breast carcinoma cells. LfcinB caused DNA fragmentation and morphological changes consistent with apoptosis in MDA-MB-435 breast cancer cell cultures, but did not affect the viability of untransformed mammary epithelial cells. MDA-MB-435 breast cancer cells also exhibited DNA fragmentation and morphological changes consistent with apoptosis following exposure to the cell-permeable ceramide analog C6. An additive increase in DNA fragmentation was observed when both LfcinB and C6 ceramide were added to MDA-MB-435 breast cancer cell cultures. A greater than additive increase in DNA fragmentation was seen when LfcinB was used in combination with tamoxifen, which prevents the metabolism of endogenous ceramide to glucosylceramide by glucosylceramide synthase, as well as blocking estrogen receptor signaling. However, a selective inhibitor of glucosylceramide synthase,1-phenyl-2-palmitoylamino-3-morpholino-1-propanol, failed to further increase DNA fragmentation by LfcinB, suggesting that tamoxifen enhanced LfcinB-induced apoptosis in breast cancer cells via a mechanism that did not involve glucosylceramide synthase inhibition. We conclude that combination therapy with LfcinB and tamoxifen warrants further investigation for possible use in the treatment of breast cancer.

Topics: Animals; Anti-Bacterial Agents; Antineoplastic Agents, Hormonal; Apoptosis; Breast; Breast Neoplasms; Cattle; Cells, Cultured; Ceramides; Epithelial Cells; Humans; Lactoferrin; Receptors, Estrogen; Tamoxifen