(M1330-05-33) Chemotherapy and Acute Lymphoblastic Leukemia–Induced Liver Fibrosis is Associated with the eIF2α Stress Response Pathway and ATGL Activation

Purpose: Acute lymphoblastic leukemia (ALL) is the most common pediatric cancer. Clinical studies have identified ALL cells in hepatic sinusoids, where hepatic stellate cells (HSCs) reside, and investigations examining the effect of ALL on the liver have demonstrated that liver fibrosis occurs in 31% of children with ALL prior to treatment. Chemotherapeutic agents used in ALL treatment, including asparaginase (ASNase), are associated with the development of liver fibrosis, and these effects can be further exacerbated in patients with ALL. Our previous work demonstrated that ASNase-induced liver injury is linked to activation of adipose triglyceride lipase (ATGL) in adipocytes. Prior research has shown that ATGL can also facilitate retinol hydrolysis and release from HSCs. However, the mechanisms underlying the clinically relevant interaction between ALL and chemotherapy in promoting liver fibrosis, and the specific role of ATGL, remain poorly understood.

Methods: Eight-week-old C57BL/6 mice were engrafted with BCR-ABL-mediated B cell ALL cells or PBS and monitored for 23 days using In Vivo Imaging System. Mice were euthanized, and blood and liver samples were collected. Liver sections underwent H&E to assess ALL infiltration, immunohistochemistry (α-SMA expression), and Sirius Red staining for collagen deposition. A parallel group received a single intraperitoneal dose of PEG-ASNase (1,500 IU/kg) or PBS. Fibrosis-related gene and protein expression (α-SMA, TGF-β, COL1α1, COL1α2) were analyzed. In the BCR-ABL model, cytokine levels (IL-1β, IFN-γ, IL-6, TNF-α, TGF-β) were measured in serum, liver, and cell lysates. Supernatants and lysates from BCR-ABL and human SUP-B15 cells, which also harbor the BCR-ABL translocation, were used to treat LX-2 cells, with or without cytokine receptor inhibitors (infliximab, tocilizumab, anakinra, emapalumab, SB-431542).

Results: ALL infiltration and ASNase treatment were associated with increased α-SMA expression and collagen deposition, indicating HSC activation. Both ALL and ASNase also induced the activation of ATGL and eIF2α. In the BCR-ABL model, elevated pro-inflammatory and pro-fibrotic cytokines (IL-1β, IFN-γ, IL-6, TNF-α, TGF-β) concentrations and mRNA levels were detected in serum, liver, and BCR-ABL cells. ALL cell supernatants induced fibrotic markers (α-SMA, TGF-β, COL1α1, COL1α2) in LX-2 cells, and this effect was attenuated by cytokine receptor inhibitors, suggesting a role for cytokine signaling in the ALL-mediated liver fibrosis.

Conclusion: Our study demonstrates that both ALL and ASNase therapy promote hepatic stellate cell activation and liver fibrosis and are associated with eIF2α phosphorylation and ATGL activation. ALL-derived pro-inflammatory cytokines further amplify fibrotic gene expression. These findings highlight a previously unrecognized role of ALL–liver crosstalk and chemotherapy in driving hepatic fibrosis and suggest potential therapeutic targets to mitigate liver injury in ALL patients

Acknowledgements:

Funding: R01DK140079, TL1-TR001858