Effect of As2O3 on colorectal CSCs stained with ALDH1 in primary cell culture in vitro.

Colorectal carcinoma (CRC) is one of the most common types of malignant tumor in humans, and its morbidity is on the increase in economically transitioning countries. Due to its high toxicity, the use of the Chinese Traditional Medicine arsenic (As2O3) is limited. However, certain studies have reported that As2O3 induces differentiation of tumor cells, promotes tumor cell apoptosis and inhibits tumor cell proliferation, although the number of studies on the effects of As2O3 on cancer stem cells (CSCs) of CRC is limited. In order to research the effects of different concentrations of As2O3 on CRC cells and colorectal CSCs in vitro, aldehyde dehydrogenase 1 (ALDH1) was sued to stain the cytoplasm of colorectal CSCs and DAPI was used to stain the nuclei of all tumor cells. Through observing the effect of different concentrations of As2O3 on CRC cells and colorectal CSCs, it was demonstrated that a sufficient concentration of As2O3 clearly inhibited the conversion from colorectal CSCs to CRC cells and increased the density of CSCs.