Study of TRAIL and SAHA Co-Treatment on Leukemia K562 Cell Line

Abstract

TRAIL (Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand) is an attractive agent being considered a potential cancer treatment. It attaches to its death receptors, leading many cancer cells to apoptosis. However, some malignancies indicate substantial resistance to TRAIL, challenging anticancer scientists. Herein, combination therapy with TRAIL plus SAHA (Suberoyl Anilide Hydroxamic Acid) was conducted to evaluate the capability of SAHA to overcome TRAIL resistance in the leukemia K562 cell line. First, the IC₅₀ for SAHA was calculated (2 µM) at 12, 24, 48, and 72 h of treatment using MTT assay. Second, the K562 cells were treated with concentrations of 50 and 100 nM of TRAIL and 2 μM of SAHA separately and together for 24, 48, and 72 h and the survival of these cells was evaluated by Flowcytometry following the annexin-V and PI staining. To demonstrate the non-toxicity of the combined treatment for normal cells, the HEK-293 cell line was treated with the TRAIL 100 nM and SAHA 2 μM combined and separated at the same periods. In the end, by performing real-time PCR, the amount of candidate genes' expression implicated in TRAIL resistance, and the levels of BCR-ABL expression was measured. The drug dosages were not toxic to normal cells. SAHA plus TRAIL strongly triggered apoptosis in K562 cells after 24, 48, and 72 h of exposure. Furthermore, it was shown that DR4, DR5, and CHOP expressions were enhanced, and PI3K, Akt, ERK, STAT3, c-FLIPL, NF-κB, and BCR-ABL expressions were decreased by SAHA in K562 cells. Our study indicated that SAHA combined with TRAIL can increase the sensitivity of K562 leukemic cells to TRAIL by suppressing intracellular anti-apoptotic molecules and augmenting the expressions of DR4/DR5 and CHOP.

Keywords: Apoptosis; Hematologic Malignancy; K562; Resistance; SAHA; TRAIL.