Effective Targeting Survivin, Caspase-3 and MicroRNA-16-1 Expression by Methyl-3-pentyl-6-methoxyprodigiosene Triggers Apoptosis in Colorectal Cancer Stem-Like Cells

Abstract

Over-expression of the proto-oncogene survivin in colorectal cancer stem cells (CCSCs) is thought to be one the primary causes for therapy failure. It has also been reported that tumor suppressor miR-16-1 is down-regulated in colorectal cancer (CRC) cells. Therefore, the search for new anti-proliferative agents which target survivin or miR-16-1 in CCSCs is warranted. Several studies have shown that prodigiosin isolated from cell wall of Serratia marcescens induces apoptosis in different kinds of cancer cells. Here, we investigated the effects of prodigiosin on HCT-116 cells that serve as a model for CRC initiating cells with stem-like cells properties. HCT-116 cells were treated with 100, 200 and 400 nM prodigiosin after which cell number, viability, growth-rate, survivin and miRNA-16-1 expression, caspase-3 activation and apoptotic rate were evaluated. Prodigiosin decreased significantly growth-rate in a dose-and time-dependent manner. After a 48 h treatment with 100, 200 and 400 nM prodigiosin, growth-rates were measured to be 84.4 ± 9.2 %, 58 ± 6.5 % and 46.3 ± 5.2 %, respectively, compared to untreated cells. We also found that treatment for 48 h with indicated concentrations of prodigiosin resulted in 41 %, 54.5 % and 63 % decrease in survivin mRNA levels and induced 32 %, 48 % and 61 % decrease in survivin protein levels as well as resulted in 128.3 ± 10 %, 178.7 ± 6.1 % and 205 ± 7.6 % increase in caspase-3 activation respectively compared to untreated cells. Prodigiosin caused a significant increase in miRNA-16-1 expression at a concentration of 100 nM and treatment with different concentrations of prodigiosin resulted in 2.2- to 3-fold increase in miRNA-16-1/survivin ratios compared to untreated cells. An increase in number of apoptotic cells ranging from 28.2 % to 86.8 % was also observed with increasing prodigiosin concentrations. Our results provide the first evidence that survivin and miRNA-16-1 as potential biomarkers could be targeted in CRC initiating cells with stem-like cells properties by prodigiosin and this compound with high pro-apoptotic capacity represents the possibility of its therapeutic application directed against CCSCs.

Deregulation of cancer-stem-cell-associated miRNAs in tissues and sera of colorectal cancer patients

“…The downregulation of miR-16 occurs in a number of solid tumours, including CRC, and is associated with the inhibition of cell proliferation by modulating the TP53/ survivin pathway [58]. Triggering its expression in CRC can lead to cancer inhibition via the intrinsic apoptosis pathway [59]. Consistent with this scenario, we clearly demonstrated that miR-16 expression was dramatically downregulated in all the CSC models of this study.…”

Targeting microRNAs: a new action mechanism of natural compounds

“…A latest Iran study found that prodigiosene can induce apoptosis in colorectal cancer stem-like cells by increasing the expression of miR-16-1 and decreasing its target gene, survivin. As it is believed that overexpression of survivin in cancer stem-like cells lead to the failure of clinical drug administration, prodigiosebne could be a good choice for fighting against this obstacle in counties with high morbidity and mortality of colorectal cancer, such as Iran [35]. …”

Prodigiosin produced bySerratia marcescensinhibits expression of MMP-9 and survivin and promotes caspase-3 activation with induction of apoptosis in acute lymphoblastic leukaemia cells

“…; Sam et al . ; Yenkejeh et al . ), with selective cytotoxicity on malignant cells and low toxicity on normal cells (Montaner et al .…”

“…Prodigiosin (Fig. 1; 2-methyl-3-pentyl-6-methoxyprodigiosene) is a natural red pigment isolated from Serratia marcescens that exerts an apoptotic effect on different kinds of cancer cells, such as hepatocellular carcinoma, colorectal cancer and acute leukaemia (Montaner et al 2000;Hassankhani et al 2015;Sam et al 2016;Yenkejeh et al 2017), with selective cytotoxicity on malignant cells and low toxicity on normal cells (Montaner et al 2000;Francisco et al 2007).…”