Abstract 1858: Saffron restricts MACC1-dependent cell proliferation and motility of colorectal cancer cells, and alters the microbiome structure
Authors: Güllü Nazli , Kobelt Dennis , Brim Hassan , Timm Lena , Smith Janice , Shoraka Hamid , Soleimani Akbar , Bisti Silvia , Gondre-Lewis Marjorie , Ashktorab Hassan , Stein Ulrike S. 
Published: August 2019

Saffron has proven a beneficial effect as a supplement in the treatment of many conditions through its perceived anti-oxidative and anti-inflammatory properties. We previously identified the gene MACC1 and demonstrated its importance as metastasis inducer, prognostic and predictive biomarker for colorectal cancer (CRC). It is confirmed as decisive driver for tumorigenesis and metastasis for a broad range of solid cancers. Therefore, we explored the inhibitory impact of saffron extracts on MACC1-induced cancer cell growth and motility and its effects on the gut microbiome. First, we assessed cell proliferation of MACC1-high and MACC1-low expressing cells using MTT and the IncuCyte real-time cell imaging system. We employed the endogenously MACC1-low expressing colon cancer cell line SW480 and clones with ectopic MACC1 overexpression. In addition, SW620 cells with endogenous high MACC1 expression and CRISPR-Cas9 mediated MACC1 knock-out were used. Cells were treated with increasing amounts of extracts from 4 different saffron species and concentration-dependent proliferation was analyzed by MTT assay. Changes in cell cycle were assessed by FACS. In vitro migration was measured by Boyden chamber assays. Activation of caspases was analyzed by Western blot. In addition, rats treated with saffron had their gut microbiome analyzed through 16S rDNA sequencing of fecal DNA samples. Upon addition of saffron, cells with high MACC1 expression showed a growth delay compared to cells with reduced MACC1 expression. Further, MACC1-dependent migration was reduced when cells were treated with saffron extracts. We did not find activation of caspases, but we showed a cell cycle arrest of MACC1 positive cells treated with saffron extracts. Using real-time measurement of cell proliferation we identified crocin as most active compound, in our system. Furthermore, rats fed with saffron showed major changes at the phylum level of their gut microbiome. A dramatic reduction/depletion of Cyanobacteria and Proteobacteria and a decrease of Bacteroidetes/Firmicutes ratio was found within the saffron treated rats. These reductions were accompanied by enrichment in Spirochaetes, Tenericutes and Candidatus saccharribacteria phyla in these rats. This is the first identification of saffron-based compounds restricting cancer cells proliferation and motility progression via the novel target MACC1. In addition, change of microbiome composition by saffron favors short chain fatty acid synthesis. The use of saffron or some of its extracts might be of therapeutic value to CRC patients.

Citation Format: Nazli Güllü, Dennis Kobelt, Hassan Brim, Lena Timm, Janice Smith, Hamid Shoraka, Akbar Soleimani, Silvia Bisti, Marjorie Gondre-Lewis, Hassan Ashktorab, Ulrike S. Stein. Saffron restricts MACC1-dependent cell proliferation and motility of colorectal cancer cells, and alters the microbiome structure [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1858.