The SPATA20 Gene Modifies Rectal Cancer Radiosensitivity

Abstract

INTRODUCTION: Rectal cancer response to neoadjuvant chemoradiotherapy correlates with outcomes, and is highly variable between patients, ranging from a complete response to minimal or no response. We have previously identified an association between SPATA20 gene expression and response in patients. The goal of this study was to establish and test a rectal cancer cell model to study SPATA20. METHODS: HRT18 rectal cancer cell lines were transfected with a lentiviral construct containing small interfering RNAs (siRNA) targeting SPATA20 mRNA to create knockdown cell lines. Western blot was subsequently used for knockdown validation. Wildtype HRT18 and knockdown HRT18 cell lines were plated in 96 well plates and subsequently irradiated with 10 Gy. Cell viability was assessed at 24 hours interval using CellTiter-Glo Luminescent Cell Viability Assay for both irradiated and non-irradiated controls (Figure 1). RESULTS: Decreased expression of SPATA20 was confirmed in knockdown HRT18 cell lines compared with wildtype HRT18 using Western blot. SPATA20 knockdown by itself did not significantly affect cell viability (p = 0.18). Knockdown SPATA20 cells were significantly more sensitive to radiation when compared with wildtype cells, resulting in a 17% decrease in cell viability (p < 0.0001). CONCLUSION: We established a SPATA20 knockdown rectal cancer model to study the effects of radiation. Manipulation of SPATA20 correlates with radiation response, signifying it as a possible modulator of radiosensitivity in rectal cancer.