IL-15 Plus Thymosin α1 Reduces Senescent Hepatic CD8(+) T Cells in Hepatocellular Carcinoma via PI3K/AKT Suppression
Wu F, Guo Z, Guan J, Xu J, Chen Y, Chen Z
Journal of Gastroenterology and Hepatology (2026)
In aged-mouse orthotopic hepatocellular carcinoma, IL-15 plus Thymosin α1 combination therapy suppressed tumor growth, prolonged survival, and reversed CD8+ T cell senescence by attenuating PI3K/AKT signalling — the first mechanistic study to combine Thymosin α1's thymic-rejuvenation effect with IL-15-driven peripheral CD8+ T cell rescue in age-related cancer.
This mechanistic study from the State Key Laboratory for Diagnosis and Treatment of Infectious Diseases at the First Affiliated Hospital of Zhejiang University tests the hypothesis that combining two T-cell-rejuvenating agents — interleukin-15 (which rescues senescent CD8+ T cells peripherally) and Thymosin α1 (which replenishes the T-cell pool via thymic rejuvenation) — synergistically overcomes the immunosenescence that drives age-related hepatocellular carcinoma progression.
The investigators established an orthotopic HCC model in aged C57BL/6 mice (22-26 months old) and randomised them to receive saline, IL-15, Thymosin α1, or combination therapy. Tumor progression was monitored by bioluminescence imaging, survival, and histopathology; hepatic CD8+ T cell phenotype and function were characterised by multicolor flow cytometry, immunofluorescence, transcriptomic sequencing, and Western blot. In vitro validation used primary human CD8+ T cells co-cultured with Huh7 hepatoma cells.
The combination significantly suppressed tumor growth and prolonged survival, reduced the proportion of senescent CD8+ T cells, expanded activated effector populations, enhanced proliferative capacity, and upregulated cytotoxic mediators (granzyme B, perforin, interferon-γ). Mechanistically, the combination attenuated chronically overactivated PI3K/AKT signalling, and the protein kinase B agonist SC79 abrogated the therapeutic effects in vitro, confirming pathway dependence.
The abstract does not report sample size per treatment arm, dosing for either IL-15 or Thymosin α1, treatment duration, or absolute tumor-volume / survival numbers — these load-bearing quantitative parameters must be verified from the full paper before downstream citation.
The orthotopic HCC mouse model in aged C57BL/6 mice (22-26 months) is the strongest available age-related cancer model, but translation to human HCC is limited by the standard cross-species caveats. The mechanistic claim of PI3K/AKT dependence rests on a single AKT-agonist rescue experiment (SC79); independent genetic-knockout confirmation would strengthen the case.
No human in-vivo data — the human component is in-vitro Huh7 co-culture only. The combination-therapy benefit is reported relative to monotherapy and saline; the additive-vs-synergistic decomposition is not explicit in the abstract. The clinical implication (combining IL-15 with Thymosin α1 in HCC immunotherapy) is interesting but speculative — no human trials of this combination exist. Single-laboratory, unreplicated.
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