The Combination of PF-543 and TRAIL Effectively Induces Apoptotic Cell Death and Inhibits Stem Cell-Like Properties Through the SPHK1/S1PR1/STAT3 Pathway in TRAIL-Resistant Colorectal Cancer Cells

  • Dig Dis Sci. 2025 Jun 5. doi: 10.1007/s10620-025-09091-y.
Se Lim Kim  1  2 ,  Min Woo Shin  1  2 ,  Byung Chul Jin  1  2 ,  Seung Young Seo  #  3  4 ,  Sang Wook Kim  #  1  2
Affiliations
  • 1. Department of Internal Medicine, Research Institute of Clinical Medicine of Jeonbuk National University Medical School, 20, Geonji-ro, Deokjin-gu, Jeonju, Jeonbuk, 54907, Republic of Korea.
  • 2. Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, 54907, Korea.
  • 3. Department of Internal Medicine, Research Institute of Clinical Medicine of Jeonbuk National University Medical School, 20, Geonji-ro, Deokjin-gu, Jeonju, Jeonbuk, 54907, Republic of Korea. [email protected].
  • 4. Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, 54907, Korea. [email protected].
  • # Contributed equally.
PMID: 40467915 DOI: 10.1007/s10620-025-09091-y
Abstract

Purpose: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces Apoptosis in various tumor cell types. Although TRAIL can directly trigger cell death, Cancer cells may acquire resistance to its apoptotic effects during treatment. Sphingosine kinase 1 (SphK1) is a key regulator of Cancer progression and resistance to therapy. In this study, we determined whether combining TRAIL with PF-543, a specific SphK1 Inhibitor, could circumvent TRAIL resistance in previously established TRAIL-resistant colorectal Cancer cells (HCT116-TR cells).

Methods: HCT116-TR cells were treated with TRAIL and/or PF-543. Apoptotic cell death and signaling pathways were evaluated using MTT assay, colony formation assay, and flow cytometry analysis. Cell aggressiveness and Cancer stemness were assessed through wound healing assay, Matrigel-coated Transwell assay, and tumorsphere formation assay. The underlying molecular mechanisms were examined by Western blotting.

Results: Combined treatment with PF-543 significantly enhanced TRAIL-induced Apoptosis in HCT116-TR cells and exhibited a synergistic effect. Mechanistically, PF-543 sensitized HCT116-TR cells to TRAIL by activating the mitochondrial Apoptosis pathway. Moreover, PF-543 increased TRAIL sensitivity by regulating DcR1 and DR5 through the SphK1/S1PR1/STAT3 pathway. In addition, combination treatment reduced the aggressiveness and Cancer stemness of HCT116-TR cells by modulating the epithelial-mesenchymal transition (EMT) pathway as well as Cancer stemness markers.

Conclusion: We identified the molecular mechanisms underlying acquired TRAIL resistance in CRC cells and suggest that targeting SphK1 represents a potential strategy to overcome TRAIL resistance and inhibit CRC metastasis.

Keywords
Apoptosis; Cancer stem cells; Chemoresistance; Colorectal cancer; Invasion; PF-543; S1PR1; SPHK1; STAT3; TRAIL.
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