Silk fibroin peptide suppresses proliferation and induces apoptosis and cell cycle arrest in human lung cancer cells.

Abstract

Silkworm cocoon was recorded to cure carbuncle in the Compendium of Materia Medica. Previous studies have demonstrated that the supplemental silk protein sericin exhibits anticancer activity. In the present study, we investigated the effects of silk fibroin peptide (SFP) extracted from silkworm cocoons against human lung cancer cells in vitro and in vivo and its possible anticancer mechanisms. SFP that we prepared had high content of glycine (~ 30%) and showed a molecular weight of ~ 10 kDa. Intragastric administration of SFP (30 g/kg/d) for 14 days did not affect the weights, vital signs, routine blood indices, and blood biochemical parameters in mice. MTT assay showed that SFP dose-dependently inhibited the growth of human lung cancer A549 and H460 cells in vitro with IC50 values of 9.921 and 9.083 mg/mL, respectively. SFP also dose-dependently suppressed the clonogenic activity of the two cell lines. In lung cancer H460 xenograft mice, intraperitoneal injection of SFP (200 or 500 mg/kg/d) for 40 days significantly suppressed the tumor growth, but did not induce significant changes in the body weight. We further examined the effects of SFP on cell cycle and apoptosis in H460 cells using flow cytometry, which revealed that SFP-induced cell cycle arrest at the S phase, and then promoted cell apoptosis. We demonstrated that SFP (20-50 mg/mL) dose-dependently downregulates Bcl-2 protein expression and upregulates Bax protein in H460 cells during cell apoptosis. The results suggest that SFP should be studied further as a novel therapeutic agent for the treatment of lung cancer.

• Authors: Mei-Sa Wang, Yi-Bo Du, Hui-Ming Huang, Zhong-Ling Zhu, Shuang-Shuang Du, Shao-Yong Chen, Hong-Ping Zhao, Zhao Yan
• Journal: Acta pharmacologica Sinica (Acta Pharmacol Sin) Vol. 40 Issue 4 Pg. 522-529 (Apr 2019) ISSN: 1745-7254 [Electronic] United States
• PMID: 29921888 (Publication Type: Journal Article)

Chemical References

• Antineoplastic Agents
• Peptides
• Fibroins

Topics

• A549 Cells
• Animals
• Antineoplastic Agents (chemistry, pharmacology)
• Apoptosis (drug effects)
• Cell Cycle Checkpoints (drug effects)
• Cell Proliferation (drug effects)
• Cell Survival (drug effects)
• Dose-Response Relationship, Drug
• Drug Screening Assays, Antitumor
• Female
• Fibroins (chemistry, pharmacology)
• Humans
• Lung Neoplasms (drug therapy, pathology)
• Male
• Mice
• Mice, Inbred BALB C
• Peptides (chemistry, pharmacology)
• Structure-Activity Relationship