Investigating the Biological Activities of Human pro-IGF-I Eb-peptide on Human Cancer Cells

Date of Completion

January 2011

Keywords

Biology, Molecular|Biology, Cell

Degree

Ph.D.

Abstract

The E-peptide of pro-insulin-like growth factor-I (pro-IGF-I) is produced by proteolytic cleavage of pre-pro-IGF-I during post-translational processing. Previous studies in Dr. Thomas T. Chen's laboratory have demonstrated that recombinant rainbow trout Ea4-peptide (rtEa4) of pro-IGF-I and chemical synthetic human Eb-peptide (shEb) of pro-IGF-I exhibit biological activities including induction of morphological differentiation, inhibition of anchorage-independent cell growth and suppression of invasion and induction of apoptosis in several human cancer cell lines. We hypothesize that recombinant human Eb-peptide may possess same spectrum of anti-tumor activity in a variety of cancer cell lines. In this project, we used a E. coli C41 (DE3) expression system and affinity column chromatography to produce and semi-purify recombinant human Eb-peptide (rhEb). Recombinant human Ebpeptide induces cell morphology change of MDA-MB-231 (human breast cancer cell), HepG2 (human liver cancer cell), PC-3 (human prostate cancer cell), and HT-29 (human column cell). The rhEb-peptide suppresses the colony formation in MDA-MB-231, HepG2, PC-3 and HT-29. The rhEb-peptide significantly reduces the invasion ability of MDA-MB-231, HepG2 and PC-3. The rhEb-peptide leads to cancer cell death in MDA-MB-231, HepG2, PC-3 and HT-29 via apoptosis. The regulation of gene expression is related to metastasis, angiogenesis and apoptosis induced by the rhEb-peptide in human cancer cells. The results show that metastatic gene expression of fibronectin 1 and laminin receptor are up regulated and urokinase-type plasminogen activator (uPA) and tissue-type plasminogen activator (tPA) are down regulated by induction of the rhEb-peptide in human cancer cells. The expression of angiogenetic gene, vascular endothelial growth factor (VEGF) is down regulated and thrombospondin 1 is up regulated by induction of rhEb in cancer cells. The apoptotic gene expression of Bcl-2 and survivin are down regulated in human cancer cells induced by rhEb. The apoptotic gene, caspase-3 and p53 are up regulated by induction of rhEb in cancer cells. ^ Keyword: pro-insulin-like growth factor-I (pro-IGF-I), E-peptide, E. coli expression system, affinity column chromatography, MDA-MB-231 (human breast cancer cell), HepG2 (human liver cancer cell), PC-3 (human prostate cancer cell), HT-29 (human column cell), gene regulation, metastasis, angiogenesis, apoptosis, fibronectin 1, laminin receptor, urokinase-type plasminogen activator (uPA), tissue-type plasminogen activator (tPA), vascular endothelial growth factor (VEGF), thrombospondin 1, Bcl-2, survivin, caspase-3, p53. ^

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