Organic extract of streptomyces induces apoptosis, anti-proliferation and cell-cycle arrest in colon cancer cells: caco-2 and HCT116 cell line as surrogate model

Colorectal cancer (CRC) is a prevalent and very lethal malignancy, resulting in more than one million deaths and nearly two million newly diagnosed cases in the year 2018. Streptomyces bacteria are a potential source of conventional compounds, as their extract contains bioactive chemicals with antiproliferative effects in cell culture settings. The aim of this research was to investigate the antiproliferative effects of the Streptomyces ethyl acetate fraction against the Caco-2 and HCT116 cell line in addition to its fundamental mechanisms.

We examined the effects of Streptomyces extract on colon cancer cell lines Caco-2 and HT-116 by incubating the cells with and without the extract. Antiproliferative effects are analyzed using the MTT cell proliferation assay, cell cycle analysis and flow cytometric detection of Annexin V/PI apoptosis. The formation of intracellular ROS was measured, in addition to Western Blot for Bax, Bcl2 and caspase-3 activation.

Our findings showed the dose-dependent inhibition of cell growth by streptomyces extract. Both Caco-2 and HT-116 cells treated with streptomyces extract displayed the beginning of apoptotic events and G1 cell-cycle arrest. Additionally, treat with the streptomyces extract significantly increased (P<0.05) ROS production, Bax and cleaved-caspase-3 were increased, while Bcl-2 was downregulated, as determined by western blotting.