Lobaplatin is a third-generation
platinum-based
antineoplastic agent and is widely used for
osteosarcoma treatment before and after
tumor removal. However, treatment failure often results from
lobaplatin drug resistance. In our study, we found that SaOS-2 and SOSP-9607
osteosarcoma cells became less sensitive to
lobaplatin after treatment with exogenous
interleukin (IL)-6. Quantitative proteomic analysis was performed to elucidate the underlying mechanism in SaOS-2
osteosarcoma cells. Cells were divided into a control group (CG), a
lobaplatin treatment group (LG), a recombinant human
IL-6 (rhIL-6), and a
lobaplatin treatment group (rhILG). We performed three biological replicates in each group to compare the differential
protein expression between groups using a tandem mass tag (TMT) labeling technology based on liquid chromatography-tandem mass spectrometry (LC-MS/MS). A total of 1,313
proteins with significant differential expression was identified and quantified. The general characteristics of the significantly enriched
proteins were identified by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses, and
protein-
protein interaction (PPI) analysis was conducted using IntAct and STRING. In total, 31
proteins were further verified by parallel reaction monitoring (PRM), among which
ras GTPase-activating protein-binding
protein 1 (G3BP1),
fragile X mental retardation syndrome-related
protein 1 (hFXR1p), and far upstream
element-
binding protein 1 (FUBP1) were significantly differentially expressed. Immunohistochemistry results showed that these three
proteins are highly expressed in specimens from
platinum-resistant
osteosarcoma patients, while the
proteins are negatively or weakly expressed in specimens from
platinum-sensitive
osteosarcoma patients. The immunofluorescence staining results were in accord with the immunohistochemistry staining results.
siRNA knockdown of FUBP1 showed a strikingly decreased IC50 value for
lobaplatin in FUBP1-silenced cells, which verified the role of FUBP1 in the drug susceptibility of
osteosarcoma and the potential therapeutic value for increasing the sensitivity to
lobaplatin. This is the first proteomic study on a rhIL-6 intervention before
lobaplatin treatment in
osteosarcoma cells.