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Updated: Oct 17, 2025
Author Spotlight: Replicating Human Osteosarcoma Progression in Immunodeficient Mice for Cancer Study
Published on: March 22, 2024
Identification of GPC3 mutation and upregulation in a multidrug resistant osteosarcoma and its spheroids as
Jun-Hua Nie1, Tao Yang2, Hong Li3
1School of Medicine, South China University of Technology, Guangzhou 510006, China.
Background:
Drug resistance and the lack of molecular therapeutic target are the main challenges in the management of osteosarcomas (OSs). Identification of novel genetic alteration(s) related with OS recurrence and chemotherapeutic resistance would be of scientific and clinical significance.
Methods:
To identify potential genetic alterations related with OS recurrence and chemotherapeutic resistance, the biopsies of a 20-year-old male osteosarcoma patient were collected at primary site (p-OS) and from its metastatic tumor (m-OS) formed after 5 months of adjuvant chemotherapy. Both OS specimens were subjected to cancer-targeted next generation sequencing (NGS) and their cell suspensions were cultured under three-dimensional condition to establish spheroid therapeutic model. Transcript-oriented Sanger sequencing for GPC3, the detected mutated gene, was performed on RNA samples of p-OS and m-OS tissues and spheroids. The effects of anti-GPC3 antibody and its combination with cisplatin on m-OS spheroids were elucidated.
Results:
NGS revealed 4 mutations (GPC3, SOX10, MDM4 and MAPK8) and 6 amplifications (MDM2, CDK4, CCND3, RUNX2, GLI1 and FRS2) in p-OS, and 3 mutations (GPC3, SOX10 and EGF) and 10 amplifications (CDK4, CCND3, MDM2, RUNX2, GLI1, FRS2, CARD11, RAC1, SLC16A7 and PMS2) in m-OS. Among those alterations, the mutation abundance of GPC3 was the highest (56.49%) in p-OS and showed 1.54 times increase in m-OS. GPC3 transcript-oriented Sanger sequencing confirmed the mutation at 1046 in Exon 4, and immunohistochemical staining showed increased GPC3 production in m-OS tissues and its spheroids. EdU cell proliferation and Calcein/PI cell viability assays revealed that of the anti-OS first line drugs (doxorubicin, cisplatin, methotrexate, ifosfamide and carboplatin), 10 μM carboplatin exerted the best inhibitory effects on the p-OS but not the m-OS spheroids. 2 μg/mL anti-GPC3 antibody effectively committed m-OS spheroids to death by itself (76.43%) or in combination with cisplatin (92.93%).
Conclusion:
This study demonstrates increased abundance and up-regulated expression of mutant GPC3 in metastatic osteosarcoma and its spheroids with multidrug resistance. As GPC3-targeting therapy has been used to treat hepatocellular carcinomas and it is also effective to OS PDSs, GPC3 would be a novel prognostic parameter and therapeutic target of osteosarcomas.
Insights
Increased GPC3 expression in metastatic osteosarcoma (OS) correlates with drug resistance. Targeting GPC3 with antibodies offers a promising therapeutic strategy for osteosarcoma, potentially overcoming resistance to conventional chemotherapy.
Area of Science:
- Oncology
- Genetics
- Molecular Biology
Background:
- Osteosarcoma (OS) management faces challenges due to drug resistance and lack of molecular targets.
- Identifying genetic alterations linked to OS recurrence and chemoresistance is crucial for clinical advancement.
Purpose of the Study:
- To identify genetic alterations associated with osteosarcoma recurrence and chemotherapeutic resistance.
- To investigate the therapeutic potential of targeting GPC3 in osteosarcoma.
Main Methods:
- Next-generation sequencing (NGS) and Sanger sequencing were used to analyze genetic mutations in primary and metastatic OS.
- Three-dimensional spheroid models were established for therapeutic evaluation.
- The efficacy of anti-GPC3 antibody, alone and with cisplatin, was assessed on metastatic OS spheroids.
Main Results:
- NGS identified mutations and amplifications in primary and metastatic OS, with GPC3 showing the highest mutation abundance and increased expression in metastatic samples.
- Metastatic OS spheroids exhibited resistance to standard chemotherapies.
- Anti-GPC3 antibody demonstrated significant efficacy in reducing metastatic OS spheroid viability, enhanced by combination with cisplatin.
Conclusions:
- Mutant GPC3 is upregulated in multidrug-resistant metastatic osteosarcoma.
- GPC3 represents a novel prognostic marker and a potential therapeutic target for osteosarcoma treatment.
