Cationic Antimicrobial Peptides Derived from Crocodylus siamensis Leukocyte Extract, Revealing Anticancer Activity and Apoptotic Induction on Human Cervical Cancer Cells

• Published in: Protein Journal 2016-06, Vol.35 (3), p.202-211
• Main Authors: Theansungnoen, Tinnakorn, Maijaroen, Surachai, Jangpromma, Nisachon, Yaraksa, Nualyai, Daduang, Sakda, Temsiripong, Theeranan, Daduang, Jureerut, Klaynongsruang, Sompong
• Format: Article
• Language: English
• Subjects: Alligators and Crocodiles - blood; Amino Acid Sequence; Analysis; Animal Anatomy; Animals; Anion exchange; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - isolation & purification; Anti-Bacterial Agents - pharmacology; Antimicrobial agents; Antimicrobial Cationic Peptides - chemistry; Antimicrobial Cationic Peptides - isolation & purification; Antimicrobial Cationic Peptides - pharmacology; Antineoplastic Agents - chemistry; Antineoplastic Agents - isolation & purification; Antineoplastic Agents - pharmacology; Apoptosis; Apoptosis - drug effects; Aquatic reptiles; Bacillus pumilus; Bacteria - drug effects; Bacterial Infections - drug therapy; Biochemistry; Bioorganic Chemistry; Cancer; Cancer cells; Care and treatment; Cell Extracts - chemistry; Cell Line, Tumor; Cervical cancer; Cervix Uteri - drug effects; Cervix Uteri - pathology; Chemistry; Chemistry and Materials Science; Cholera toxin; Crocodiles; Crocodylidae; Crocodylus siamensis; Cytotoxicity; Female; Fresh water; HeLa Cells; Hemolysis - drug effects; Histology; Humans; Leukocytes - chemistry; Liquid chromatography; Mass spectrometry; Morphology; Organic Chemistry; Peptides; Uterine Cervical Neoplasms - drug therapy; Uterine Cervical Neoplasms - pathology; Vibrio cholerae
• ISSN: 1572-3887; 1573-4943; 1875-8355
• DOI: 10.1007/s10930-016-9662-1

Known antimicrobial peptides KT2 and RT2 as well as the novel RP9 derived from the leukocyte extract of the freshwater crocodile ( Crocodylus siamensis ) were used to evaluate the ability in killing human cervical cancer cells. RP9 in the extract was purified by a combination of anion exchange column and reversed-phase HPLC, and its sequence was analyzed by mass spectrometry. The novel peptide could inhibit Gram-negative  Vibrio cholerae  (clinical isolation) and Gram-positive  Bacillus pumilus  TISTR 905, and its MIC values were 61.2 µM. From scanning electron microscopy, the peptide was seen to affect bacterial surfaces directly. KT2 and RT2, which are designed antimicrobial peptides using the C. siamensis Leucrocin I template, as well as RP9 were chemically synthesized for investigation of anticancer activity. By Sulforhodamine B colorimetric assay, these antimicrobial peptides could inhibit both HeLa and CaSki cancer cell lines. The IC 50 values of KT2 and RT2 for HeLa and CaSki cells showed 28.7–53.4 and 17.3–30.8 µM, while those of RP9 were 126.2 and 168.3 µM, respectively. Additionally, the best candidate peptides KT2 and RT2 were used to determine the apoptotic induction on cancer cells by human apoptosis array assay. As a result, KT2 and RT2 were observed to induce apoptotic cell death in HeLa cells. Therefore, these results indicate that KT2 and RT2 with antimicrobial activity have a highly potent ability to kill human cervical cancer cells.