The Effect of LL37 Antimicrobial Peptide on FOXE1 and lncRNA PTCSC 2 Genes Expression in Colorectal Cancer (CRC) and Normal Cells

OBJECTIVE: As an innate immune system component, antimicrobial peptides (AMPs) exert various effects, such as anticancer properties. This study aimed to evaluate the LL37 AMP anticancer effect against colorectal cancer (CRC) cells and the expression of FOXE1 and lncRNA PTCSC2 genes. METHODS: The LL37 AMP was purchased from GenScript USA, Inc. Various CRC cell lines (HCT-116, HT29, WiDr, and SW742) were cultured in the DMEM medium. Various concentrations ranging from (5-400) μg/mL of LL37 AMP were prepared, added to cell cultures, and incubated for (24 and 48) hours. A nontoxic level of 30 µg/mL of LL37 was investigated for FOXE1 and lncRNA PTCSC2 gene expression. RESULTS: At 24 hours, the (50 and 90) % lethal concentrations of LC50 and LC90, respectively, of LL37 against NCM460 normal cells were (640 and > 640) g/mL. Additionally, these values at 48 hours included (160 and > 640) µg/mL, respectively. After 24 hours of treatment, the LC50 and LC90 of LL37 AMP against CRC cell lines included (20 and 200) µg/mL. The LC50 and LC90 of the LL37 at 48 hours included (20 and 50) µg/mL and at 72 hours. they included (~10 and 40) μg/mL, respectively. FOXE1 but not the PTCSC 2 gene expression was significantly higher in CRC cells than normal cells (NCM460 and HaCaT). The LL37 AMP significantly decreased FOXE1 gene expression by 1.95-fold in CRC cells (p < 0.001). CONCLUSION: The FOXE1 gene can be considered a biomarker of CRC development. The expression of FOXE1 but not the PTCSC2 gene was significantly affected by the LL37 AMP. The effects of LL37 AMP against CRC cells were time and dose-dependent. Future studies are warranted to verify these effects.