The influence of ALDH1A expression on chemoresistance of colon cancer cell lines

Introduction

In our study we focused on the aldehyde dehydrogenase 1A (ALDH1A) expression in colon cancer cell lines HT-29, HCT-116 and LS- 180. This gene was identified as one out of several key stem cells markers in colon cancer: ALDH1, CD133, CD44, LGR5 and others.

Materials/methods

We prepared 5-flourouracil (5-FU) resistant cell line HT-29/EGFP/ FUR. The qPCR was used for RNA analysis. Small interfering RNA (siRNA) silencing ALDH1A target gene was introduced to the cells. Western blot, qPCR, Aldefluor, cell proliferation and Annexin V assays, were used to analyse the properties of these cells. In vivo experiments were performed on athymic mouse model.

Results and conclusions

Newly prepared cell line HT-29/ EGFP/FUR was characterized. We confirmed cross resistance to different chemotherapeutics. Expression level of different isoenzymes of ALDH in tested cells was identified. We used pharmacological inhibition of ALDH expression with diethylaminobenzaldehyde (DEAB) and also molecular inhibition by siRNA specific for ALDH1A1 or ALDH1A3. We confirmed a connection between the expression of ALDH1 and a resistance to chemotherapy in some tested cell lines. Silencing of the ALDH1A1 gene can sensitise the HT-29/EGFP cells to 5-FU, and capecitabine in vitro. Tumours induced by HT-29/EGFP cells transfected with ALDH1A1 siRNA have proliferated at slower rate than cells transfected with negative siRNA in vivo. This provides the basis for the development of new approaches to the treatment of cancer patients.

Financial support

APVV-0052-12 and APVV-0230-11; VEGA 2/0171/13, 2/0130/13 and 2/0087/15. This work was partially supported by the WAC and RFL programs funded by the Slovak Cancer Research Foundation.