Researchers at the University of Adelaide have shown how a complex mix of plant compounds derived from ancient clinical practice in China, a traditional Chinese medicine, works to kill cancer cells.
Compound kushen injection (CKI) is approved for use in China to treat various cancer tumors, usually as an adjunct to western chemotherapy. But how it works has not been known.
This study is one of the first to characterise the molecular action of a Traditional Chinese Medicine rather than breaking it down to its constituent parts.
Compound Kushen Injection Therapeutic Benefit
Study leader Professor David Adelson, Director of the Zhendong Australia – China Centre for the Molecular Basis of Traditional Chinese Medicine, said:
“Most traditional Chinese medicine is based on hundreds or thousands of years of experience with their use in China. There is often plenty of evidence that these medicines have a therapeutic benefit, but there isn’t the understanding of how or why.”
The Zhendong Australia China Centre for Molecular Traditional Chinese Medicine was established at the University of Adelaide in 2012 in a collaboration with the China-based Shanxi University of Traditional Chinese Medicine and Zhendong Pharmaceutical Company.
“If we broke down and tested the components of many traditional Chinese medicines, we would find that individual compounds don’t have much activity on their own. It’s the combination of compounds which can be effective, and potentially means few side-effects as well,” explains Professor Adelson.
“This is one of the first studies to show the molecular mode of action of a complex mixture of plant-based compounds – in this case extracts from the roots of two medicinal herbs, Kushen and Baituling – by applying what’s known as a systems biology approach. This is a way of analysing complex biological systems that attempts to take into account all measurable aspects of the system rather than focussing on a single variable.”
Gene Expression Patterns
The researchers used high-throughput next generation sequencing technologies to identify genes and biological pathways targeted by compound kushen injection when applied to breast cancer cells grown in the laboratory.
“We showed that the patterns of gene expression triggered by CKI affect the same pathways as western chemotherapy but by acting on different genes in the same pathways,” says Professor Adelson.
“These genes regulate the cell cycle of division and death, and it seems that CKI alters the way the cell cycle is regulated to push cancer cells down the cell death pathway, therefore killing the cells.”
Professor Adelson says this technique could be used to analyse the molecular mechanisms of other traditional Chinese medicines, potentially opening their way for use in western medicine.
Compound Kushen Injection (CKI) has been clinically used in China for over 15 years to treat various types of solid tumours. However, because such Traditional Chinese Medicine (TCM) preparations are complex mixtures of plant secondary metabolites, it is essential to explore their underlying molecular mechanisms in a systematic fashion. We have used the MCF-7 human breast cancer cell line as an initial in vitro model to identify CKI induced changes in gene expression. Cells were treated with CKI for 24 and 48 hours at two concentrations (1 and 2 mg/mL total alkaloids), and the effect of CKI on cell proliferation and apoptosis were measured using XTT and Annexin V/Propidium Iodide staining assays respectively.
Transcriptome data of cells treated with CKI or 5-Fluorouracil (5-FU) for 24 and 48 hours were subsequently acquired using high-throughput Illumina RNA-seq technology. In this report we show that CKI inhibited MCF-7 cell proliferation and induced apoptosis in a dose-dependent fashion. We integrated and applied a series of transcriptome analysis methods, including gene differential expression analysis, pathway over-representation analysis, de novo identification of long non-coding RNAs (lncRNA) as well as co-expression network reconstruction, to identify candidate anti-cancer molecular mechanisms of CKI. Multiple pathways were perturbed and the cell cycle was identified as the potential primary target pathway of CKI in MCF-7 cells. CKI may also induce apoptosis in MCF-7 cells via a p53 independent mechanism. In addition, we identified novel lncRNAs and showed that many of them might be expressed as a response to CKI treatment.