Effect of chitooligosaccharides on cyclin D1, bcl-xl and bcl-2 mRNA expression in A549 cells using quantitative PCR

Abstract

Chitooligosaccharide (COS) is derived from the chemical and enzymatic hydrolysis of chitosan and has been reported to have potent antitumor activity. Our study investigated the effects of five chitooligomers ranging from the dimer form to the hexamer form (chitobiose, chitotriose, chitotetraose, chitopentaose, chitohexaose) on the expression of cyclin D1, bcl-2 and bcl-xl mRNA in A549 cells using reverse transcription quantitative real-time PCR. We demonstrated that, of the five chitooligomers used, chitohexaose (COS6) had the most potent inhibitory effect on A549 cell proliferation. COS6 also significantly down regulated cyclin D1 and bcl-xl mRNA expression levels. Our data suggested that COS6 exerts its antitumor activity by two different mechanisms: (1) COS6-mediated inhibition of Cyclin D1 levels leads to suppression of tumor cell proliferation; and (2) COS6-mediated down-regulation of the pro-survival protein, Bcl-xl, promotes the apoptosis of tumor cells. chitooligosaccharides, cyclin D1, bcl-xl, bcl-2 Citation:Li X, Wang J, Chen X J, et al. [6,7]. The antitumor activity of COS is likely influenced by its chemical structure, molecular size, and strong electric charge [6][7][8]. Administration of N-acetylchitohexaose (NACOS-6) resulted in a significant increase in the candidacidal activity of macrophages and T lymphocytes in the early phase of tumor development [8] and COS was suggested to play a role in the induction of apoptosis of carci-*Corresponding author (email: tcrz9@jnu.edu.cn) noma cells via up-regulation of Bax [9]. The chitohexamer form was shown to down-regulate VEGF and uPA mRNA expression levels in ECV304 cells [10], and to inhibit tumor growth and metastasis by up-regulation of p21 and MMP-9, and down-regulation of PCNA, cyclin A and cdk-2 [11]. However, the effects of different forms of COS on the expression levels of cyclin D1 and the pro-survival proteins bcl-2 and bcl-xl are unknown. In this study, we investigated the role of five different fractions [chitobiose (COS2), chitotriose (COS3), chitotetraose (COS4), chitopentaose (COS5), chitohexaose (COS6)] on the regulation of cyclin D1, bcl-2 and bcl-xl mRNA levels in A549 cells. We demonstrated that COS6 exhibited the most potent inhibitory activity on A549 cell proliferation by downregulation of cyclin D1 mRNA. Treatment of A549 cells with COS6 also resulted in suppression of bcl-xl mRNA expression levels.

Enzymatic Modifications of Chitin, Chitosan, and Chitooligosaccharides

“…The molecular weight of COS has an essential effect on anticancer activity. It has been reported that chitohexanoses are the most promising oligomers to manifest the anticancer effect (Xiong et al, 2009; Li et al, 2011). Wang et al (2007) published the results of studies confirming the influence of the degree of COS acetylation on anticancer activity.…”

Immunomodulatory Effects of N-Acetyl Chitooligosaccharides on RAW264.7 Macrophages

“…The COS are currently commercialized and widely used in cosmetics, animal husbandry, medicine, and food industries. Many bioactivities of COS have been reported, including immunoregulatory [ 7 ], antioxidant [ 8 ], anti-tumor [ 9 ], anti-bacterial [ 10 ], antihypertensive [ 11 ], and anti-diabetes [ 12 ] activities, among others.…”

The Microstructure, Antibacterial and Antitumor Activities of Chitosan Oligosaccharides and Derivatives

“…To investigate the antitumor activity of COSs, the influence of MW should also be taken into consideration in addition to the functional groups on the pyranose ring, including amino and acetyl amino groups [74]. Some studies have evaluated the antitumor differences between dimeric and hexameric COSs, with hexameric COSs showed the best effect on A549 cells [75]. In vitro studies have shown that COSs could exhibit antitumor activity on a variety of tumor cells, and in vivo experiments have shown that COSs could inhibit tumor proliferation and metastasis [76].…”