2. Academic Validation
  3. Indirect bilirubin impairs invasion of osteosarcoma cells via inhibiting the PI3K/AKT/MMP-2 signaling pathway by suppressing intracellular ROS

Indirect bilirubin impairs invasion of osteosarcoma cells via inhibiting the PI3K/AKT/MMP-2 signaling pathway by suppressing intracellular ROS

  • J Bone Oncol. 2023 Feb 23:39:100472. doi: 10.1016/j.jbo.2023.100472.
Xuhui Yuan 1 2,  Cong Ma 3,  Jiayu Li 1 2,  Junhong Li 3,  Ronghui Yu 4,  Feng Cai 1 2 4,  Gaoyang Qu 1 2 4,  Bo Yu 1 2 4,  Lang Liu 1 2 4,  Duo Zeng 1 2 4,  QuanHui Jiao 1 4,  Qi Liao 1 2,  Xiaobin Lv 1
Affiliations

Affiliations

  • 1 Jiangxi Key Laboratory of Cancer Metastasis and Precision Treatment, Central Laboratory, The First Hospital of Nanchang, The Third Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330008, China.
  • 2 Department of Orthopedics, The First Hospital of Nanchang, The Third Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330008, China.
  • 3 Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China.
  • 4 Department of Orthopedics, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China.
PMID: 36876225 DOI: 10.1016/j.jbo.2023.100472
Abstract

Background: Osteosarcoma is most prevalently found primary malignant bone tumors, with primary metastatic patients accounting for approximately 25% of all osteosarcoma patients, yet their 5-year OS remains below 30%. Bilirubin plays a key role in oxidative stress-associated events, including malignancies, making the regulation of its serum levels a potential anti-tumor strategy. Herein, we investigated the association of osteosarcoma prognosis with serum levels of TBIL, IBIL and DBIL, and further explored the mechanisms by which bilirubin affects tumor invasion and migration.

Methods: ROC curve was plotted to assess survival conditions based on the determined optimal cut-off values and the AUC. Then, Kaplan-Meier curves, along with COX proportional hazards model, was applied for survival analysis. Inhibitory function of IBIL on the malignant properties of osteosarcoma cells was examined using the qRT-PCR, transwell assays, western blotting, and flow cytometry.

Results: We found that, versus osteosarcoma patients with pre-operative higher IBIL (>8.9 μmol/L), those with low IBIL (≤8.9 μmol/L) had shorter OS and PFS. As indicated by the COX proportional hazards model, pre-operative IBIL functioned as an independent prognostic factor for OS and PFS in total and gender-stratified osteosarcoma patients (P < 0.05 for all). In vitro experiments further confirmed that IBIL inhibits PI3K/Akt phosphorylation and downregulates MMP-2 expression via reducing intracellular ROS, thereby decreasing the invasion of osteosarcoma cells.

Conclusions: IBIL may serve as an independent prognostic predictor for osteosarcoma patients. IBIL impairs invasion of osteosarcoma cells through repressing the PI3K/Akt/MMP-2 pathway by suppressing intracellular ROS, thus inhibiting its metastatic potential.

Keywords

AUC, area under curve; BRNP, PEGylated bilirubin nanoparticles; CCK-8, cell counting kit-8; CI, confidence interval; DBIL, direct bilirubin; DMSO, dimethyl sulfoxide; ECM, extracellular matrix; H2O2, hydrogen peroxide; HIF-1α, hypoxia inducible factor-1α; HR, hazard ratio; IBIL; IBIL, indirect bilirubin; Invasion; MDA, malondialdehyde; MMP, matrix metalloproteinase; OS, overall survival; Osteosarcoma; PFS, progression-free survival; PI3K/AKT/MMP-2; PVDF, polyvinylidene fluoride; Prognosis; ROC, receiver operative characteristic; ROS, reactive oxygen species; SD, standard deviation; SOD, superoxide dismutase; TBIL, total bilirubin; TIMP, tissue inhibitor of matrix metalloproteinase; VEGF, vascular endothelial growth factor; qRT-PCR, real-time quantitative PCR.

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