Correlation between the promoter methylation status of ATP-binding cassette sub-family G member 2 and drug sensitivity in colorectal cancer cell lines

Background/Aims: ADAMTS (disintegrin-like and metalloproteinase with thrombospondin motifs) proteins are extracellular zinc metalloproteinases that play an important role in extracellular matrix assembly and degradation, connective tissue structuring, angiogenesis, and cell migration. Multiple studies suggest that ADAMTS proteins (e.g. ADAMTS9) can act as tumor suppressors. In gastric, esophageal, and nasopharyngeal carcinomas ADAMTS9 is frequently down-regulated by promoter methylation. Whether ADAMTS9 can function as a tumor suppressor gene (TSG) in colorectal cancer is still unclear. Methods: We performed immunohistochemistry, RT-PCR, and qRT-PCR, to examine the expression of ADAMTS9 in colorectal cancer cell lines and primary colorectal cancer tissues. Methylation-specific PCR was also carried out to investigate the promoter methylation status of ADAMTS9. We also explored the functions of ADAMTS9 in colorectal cancer cell lines through in vitro experiments. Results: ADAMTS9 expression was down-requlated or silenced in 83.3% (5/6) of colorectal cancer cell lines, and frequently repressed in 65.6% (21/32) of colorectal cancer tissues. Down-regulation of ADAMTS9 was partially due to promoter methylation. Exogenous expression of ADAMTS9 in colorectal cancer cell lines inhibited cell proliferation and migration through the regulation of cell cycle and apoptosis. In addition, ADAMTS9 prevented the activation of Akt, and its downstream targets in colorectal cancer cell lines. Conclusion: Our findings suggest ADAMTS9 is a TSG in colorectal cancer.

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MicroRNAs related to intrinsic resistance to oxaliplatin and the irinotecan metabolite SN-38 in 10 colorectal cancer cell lines.

Journal of Clinical Oncology ◽

10.1200/jco.2012.30.4_suppl.524 ◽

2012 ◽

Vol 30 (4_suppl) ◽

pp. 524-524 ◽

Cited By ~ 2

Author(s):

Niels Frank Jensen ◽

Rolf Soekilde ◽

Jan Stenvang ◽

Birgitte Sander Nielsen ◽

Thomas Litman ◽

...

Keyword(s):

Colorectal Cancer ◽

Cell Lines ◽

Cancer Cell ◽

Drug Sensitivity ◽

Predictive Biomarkers ◽

Cancer Cell Lines ◽

Colorectal Cancer Cell ◽

Intrinsic Resistance ◽

Short Term ◽

Colorectal Cancer Cell Lines

524 Background: Chemotherapy of metastatic colorectal cancer is based on 5-flourouracil combined with either oxaliplatin or irinotecan (active metabolite: SN-38). Identification of predictive biomarkers of drug response is needed to provide a better personalized treatment. In this study we aimed to identify microRNAs related to intrinsic resistance to oxaliplatin or irinotecan in a panel of ten colorectal cancer cell lines. Methods: Drug sensitivity towards oxaliplatin and SN-38 was determined for ten colorectal cancer cell lines (Colo-205, DLD-1, HCC-2998, HCT-15, HCT-116, HT-29, KM12, LoVo, LS-174T, and SW620), using the cell viability MTT assay and the cell death LDH assay. In addition, two cell lines (DLD-1 and LoVo) were exposed to the drugs for 6, 24 or 48 hours. MicroRNA expression profiles were generated using the Exiqon miRCURY LNA microarray platform (including 840 microRNAs), and four differentially expressed microRNAs were validated by independent qRT-PCR measurements. Results: The drug sensitivities of the ten colorectal cancer cell lines varied about 50 times between the least and most sensitive cell lines. Correlation of drug sensitivity data to microRNA expression data across the ten cell lines yielded about 25 microRNA biomarker candidates, for each of the drug/assay combinations. Following short-term drug treatment 10-20 microRNAs were altered for each drug/cell line combination. Validation by qRT-PCR showed a very good correlation to the microarray data. MicroRNAs identified by correlation to drug sensitivity and by short-term treatment were compared, and less than 10% were identified by both approaches, perhaps representing the most promising candidates. These candidates are for SN-38 miR-15a, miR-22, miR-24, miR-98, miR-142-3p, miR-1290, and let-7b, and for oxaliplatin miR-23b, miR-27a, miR-192, miR-200a, miR-222, miR-886-5p, and miR-1308. Conclusions: In the present study we identified a number of microRNAs that are potentially involved in intrinsic resistance and/or could be predictive biomarkers for either irinotecan or oxaliplatin.

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