Exosomal Lnc-DLK1-35 reprograms microglia into a pro-tumorigenic phenotype via a non-canonical cytokine signature to promote glioblastoma progression and chemoresistance

  • Folia Histochem Cytobiol. 2026;64(1):48-59. doi: 10.5603/fhc.109684.
Dan Li  1  2  3 ,  Yufeng Li  4  5  6 ,  Zhuo Wang  1  2  3 ,  Xuan Zheng  1  2  3 ,  Yang Wang  1  2  3 ,  Jianxiong Guo  1  2  3 ,  Jingwu Li  1  7 ,  Yongliang Liu  1  8 ,  Yuhui Li  1  8
Affiliations
  • 1. Hebei Key Laboratory of Molecular Oncology, Tangshan People's Hospital, Hebei, China.
  • 2. Tangshan Key Laboratory of Cancer Prevention and Therapy, Tangshan People's Hospital, Hebei, China.
  • 3. The Cancer Institute, Tangshan People's Hospital, Hebei, China.
  • 4. Hebei Key Laboratory of Molecular Oncology, Tangshan People's Hospital, Hebei, China. [email protected].
  • 5. Tangshan Key Laboratory of Cancer Prevention and Therapy, Tangshan People's Hospital, Hebei, China. [email protected].
  • 6. The Cancer Institute, Tangshan People's Hospital, Hebei, China. [email protected].
  • 7. Department of Gastrointestinal Surgery, Tangshan People's Hospital, Hebei, China.
  • 8. Department of Neurosurgery, Tangshan People's Hospital, Tangshan, Hebei, China.
PMID: 41811084 DOI: 10.5603/fhc.109684
Abstract

Introduction: Temozolomide (TMZ) resistance in glioblastoma (GBM) involves dynamic crosstalk of Cancer cells with tumor-associated microglia, but the role of exosomal long non-coding RNAs (lncRNAs) remains poorly defined.

Material and methods: We isolated exosomes from TMZ-sensitive (U251) and TMZ-resistant (U251TR) GBM cells. Lnc-DLK1-35 expression was modulated by overexpression/knockdown and validated by RT-qPCR. Exosome internalization by microglia (HMC3 cells) was tracked via PKH67 labeling. Microglial polarization was assessed by studying morphology, marker expression (CD16/CD32/iNOS/Arg-1/CD206/CD163), and cytokine secretion (ELISA: IL-6, TNF-α, TGF-β, IL-10, CXCL13). Functional impact on GBM cells by indirect co-culture with IL4-activated HMC3 cells was examined using CCK-8 and Transwell assays.

Results: Lnc-DLK1-35 was enriched in U251TR cells and their exosomes. GBM exosomes delivered Lnc-DLK1-35 to microglia, inducing a unique GBM-educated phenotype: amoeboid morphology, elevated type 1 macrophage (M1) markers (CD16, iNOS) but suppressed immunoregulatory factors (IL-10, CXCL13). This reprogramming required exosomal transfer. In addition, indirect co-culture with IL4-activated HMC3 cells enhanced GBM malignancy, reduced TMZ sensitivity and promoted migration and invasion.

Conclusions: Exosomal Lnc-DLK1-35 reprograms cultured microglia cells into a pro-tumorigenic state via a non-canonical cytokine signature, driving TMZ resistance and invasion. Targeting this axis disrupts microglia-GBM communication, revealing a novel therapeutic strategy.

Keywords
exosomes; glioblastoma; microglial cells; microglial polarization; temozolomide.
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