Oridonin triggers apoptosis in colorectal carcinoma cells and suppression of microRNA-32 expression augments oridonin-mediated apoptotic effects.

Abstract

Oridonin, a bioactive diterpenoid isolated from Rabdosia rubescens, has been found to exhibit various anti-tumor effects. In this work, to investigate its pharmacological effects on human colorectal carcinoma HCT-116 and LoVo cells, cell proliferation and apoptosis were respectively evaluated by 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay, annexin V-FITC, and propidium iodide (PI) staining. Western blotting was used to detect the expression levels of Bim, Bax, Bcl-2, cytosolic cytochrome c, procaspase-9, cleaved caspase-9, procaspase-3, and caspase-3 proteins. Caspase-Glo-9 and Caspase-Glo-3 assays were applied to determine caspase-9 and caspase-3 activity. MicroRNA-32 (miR-32) expression level was detected by real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The in vivo anti-tumor effects of oridonin were evaluated using cell lines HCT-116 and LoVo xenograft model. The results indicated that oridonin effectively inhibited cell proliferation and induced apoptosis in HCT-116 and LoVo cells in a concentration-dependent manner. Oridonin treatment upregulated the expression levels of Bim, Bax, cytosolic cytochrome c, cleaved caspase-9 and cleaved caspase-3 proteins, downregulated the expression levels of Bcl-2, procaspase-9 and procaspase-3 proteins, and meanwhile obviously activated caspase-9 and caspase-3 in a dose-dependent manner in HCT-116 and LoVo cells. The results of qRT-PCR demonstrated that oridonin treatment significantly decreased miR-32 expression, and furthermore, suppression of miR-32 expression by miR-32 inhibitors augmented oridonin-mediated inhibitory and apoptotic effects in HCT-116 and LoVo cells. In vivo results indicated that oridonin administration through intraperitoneal injection suppressed tumor growth in nude mice. Therefore, these findings suggest that oridonin maybe is a potential candidate for colorectal cancer treatment.

• Authors: Jie Yang, Hai Jiang, Chunyu Wang, Bo Yang, Lijun Zhao, Dongling Hu, Guihua Qiu, Xiaolin Dong, Bin Xiao
• Journal: Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie (Biomed Pharmacother) Vol. 72 Pg. 125-34 (May 2015) ISSN: 1950-6007 [Electronic] France
• PMID: 26054686 (Publication Type: Journal Article)
• Copyright: Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Chemical References

• Antineoplastic Agents
• Apoptosis Regulatory Proteins
• BCL2L11 protein, human
• Bcl-2-Like Protein 11
• Bcl2l11 protein, mouse
• Diterpenes, Kaurane
• MIRN32 microRNA, human
• Membrane Proteins
• MicroRNAs
• Proto-Oncogene Proteins
• bcl-2-Associated X Protein
• oridonin
• Cytochromes c
• Caspase 3
• Caspase 9

Topics

• Animals
• Antineoplastic Agents (pharmacology)
• Apoptosis (drug effects, genetics)
• Apoptosis Regulatory Proteins (metabolism)
• Bcl-2-Like Protein 11
• Caspase 3 (metabolism)
• Caspase 9 (metabolism)
• Cell Line, Tumor
• Cell Proliferation (drug effects)
• Colorectal Neoplasms (enzymology, genetics, pathology)
• Cytochromes c (metabolism)
• Diterpenes, Kaurane (chemistry, pharmacology)
• Enzyme Activation (drug effects)
• Gene Expression Regulation, Neoplastic (drug effects)
• Humans
• Membrane Proteins (metabolism)
• Mice
• MicroRNAs (genetics, metabolism)
• Proto-Oncogene Proteins (metabolism)
• Xenograft Model Antitumor Assays
• bcl-2-Associated X Protein (metabolism)