Cytotoxic effect of Konjac Glucomannan on HepG2 and WRL 68 cell lines
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1
Universiti Malaya, Department of Biomedical Engineering, Faculty of Engineering, Malaysia
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2
Universiti Malaya, Department of Molecular Medicine, Faculty of Medicine, Malaysia
Liver cancer is the seventh most diagnosed cancer worldwide and the second leading cause of cancer-related death in less developed countries [1]. Hepatocellular carcinoma (HCC) is the most prevalent type with 90-95% of liver cancer cases and listed as the third most lethal neoplasms. In 2012, World Health Organization (WHO) reported 782,451 new liver cancer cases worldwide with only 2.0% survival rate [2]. High mortality rate of HCC patients is mainly due to late diagnosis as the symptoms only arise at the advanced stage leading to unsatisfactory curative effect [3]. Multiple liver cancer treatments are available; however, treatments effectiveness is highly dependent on the cancer stage, patient health status, and degree of liver-function impairment as well as the requirement for multidisciplinary approaches. Despite having channeled tremendous effort in deriving potent anti-cancer compounds from natural resources, many drugs failed to show the specificity [4]. Konjac glucomanan (KGM) is an active compound of Amorphophallus konjac, which has long been used in China, Japan and South East Asia as food sources and traditional medicines including suppression of tumour; however, this is yet to be proven scientifically in curing liver cancer [5]. The main objective of this study is to determine the effect of KGM on normal liver (WRL 68) and liver cancer (HepG2) cell lines based on MTT assay and morphological study.
Liver carcinoma cells (HepG2) and normal liver cells (WRL68) as control (American Type Culture Collection) were cultured with growth medium supplemented with 10% FBS and further subcultured as needed [6]. Cells were plated at 10,000 cells per well of 96-well plate and treated with various concentrations of sample (KGM, mannose, KGM-mannose), 5 fluorouracil (positive control) and negative control and further incubated for 24, 48 and 72 hours respectively and assessed using MTT assay [7]. The cells were observed under inverted microscope for their morphological changes at 24, 48 and 72 hours post-treatments. Student‘s t-test was done on the mean and standard deviation (SD) to determine the statistical significance. The results are significant if the p value is less than 0.05.
The percentage viability of HepG2 cells treated with KGM appears to be the lowest among the three treatments for 24, 48 and 72 hours as shown in Fig. 1(A). The mannose treatment did not affect the viability of HepG2 cells in a significant manner. Co-supplementation of KGM-mannose did not affect the cellular proliferation after 48 and 72 hours. Overall, KGM alone and in combination with mannose expressed higher cytotoxic effect against HepG2 cells. KGM have been reported to cause changes in glycoprotein synthesis in cells. It acts as alternate substrates for Golgi enzymes and alters the glycoproteins expression on cell surface [8].
Fig. 1(B) depicts that supplementations of KGM, mannose and KGM-mannose induced the proliferation of WRL 68 cells. Cell viability increased significantly compared to control. With the presence of mannose, the percentage viability of WRL 68 cells increased and reached plateau between 3 to 5 mg/mL. All three treatments showed selective inhibition on cellular proliferation of HepG2, not in WRL 68 cells. Glucomannan is the major structural component of KGM which can be recognized by large range of cell surface receptors including mannose receptor (MR). The interaction of mannosylated sugar to MR is believed to activate the downstream MAPK pathway in cells, resulting in apoptosis [9]. Our findings signify the selective activity of KGM, but not mannose in hepatocellular carcinoma suggesting these two compounds may be involve in two different pathways despite they both are from saccharide family. In conclusion, selective inhibition of proliferation of KGM-treated HepG2 cells concluded that KGM is a potential cytotoxic agent against liver cancer. Its mechanism of action remains unclear and warrant further investigation.
Acknowledgements
This research was supported by University of Malaya Research Grant (Project Numbers: RP009C-13AET, RP022C-14AFR and RP040B-15HTM) and Postgraduate Research Grant (PG072-2016A). We thank our colleagues from Department of Biomedical Engineering and Department of Molecular Medicine who provided insight and expertise that greatly assisted the research.
Keywords:
liver cancer,
cytotoxic effect,
MTT assay,
HepG2 cell line,
Morphological study,
KGM
Conference:
6th Malaysian Tissue Engineering and Regenerative Medicine Scientific Meeting (6th MTERMS) 2016 and 2nd Malaysian Stem Cell Meeting, Seberang Jaya, Penang, Malaysia, 17 Nov - 18 Nov, 2016.
Presentation Type:
Oral
Topic:
Natural Products in Regenerative Medicine
Citation:
Sawai
S,
Mokhtar
MS,
Kamarulzaman
WW and
Ramasamy
TS
(2016). Cytotoxic effect of Konjac Glucomannan on HepG2 and WRL 68 cell lines.
Front. Bioeng. Biotechnol.
Conference Abstract:
6th Malaysian Tissue Engineering and Regenerative Medicine Scientific Meeting (6th MTERMS) 2016 and 2nd Malaysian Stem Cell Meeting.
doi: 10.3389/conf.FBIOE.2016.02.00029
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Received:
08 Dec 2016;
Published Online:
19 Dec 2016.
*
Correspondence:
Ms. Sakunie Sawai, Universiti Malaya, Department of Biomedical Engineering, Faculty of Engineering, Kuala Lumpur, Selangor, 50603, Malaysia, sakunie1292@gmail.com