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Updated: Jul 12, 2026
Tumorsphere Derivation and Treatment from Primary Tumor Cells Isolated from Mouse Rhabdomyosarcomas
Published on: September 13, 2019
Reduced expression of INK4a/ARF genes in stem-like sphere cells from rat sarcomas
Hiromasa Fujii1, Kanya Honoki, Toshifumi Tsujiuchi
1Department of Orthopedic Surgery, Nara Medical University, Kashihara, Nara 634-8521, Japan.
Abstract:
The presence of cancer stem cells, in both hematopoietic and solid malignancies, has been recently linked to their pathogenesis. We aimed to identify the characteristics and stem-like properties of sphere-colony forming cells in rat osteosarcoma and malignant fibrous histiocytoma cell lines. The results showed that both cell lines possessed an ability to form spherical, clonally expanding colonies in anchorage-independent, serum-starved conditions in N2/1% methylcellulose medium. The sphere cells showed stem-like properties with the ability to self-renew, and expressed the stem cell-related STAT3 and Bmi1 genes. Interestingly, spheres from both sarcomas remarkably decreased the expression of INK4a/ARF locus genes, p16(INK4a) and p19(ARF), which could be related to the resistance against cell senescence and apoptosis. Spheres showed strong tumorigenicity with metastatic potential in vivo via the inoculation into syngeneic rats, suggesting the presence of these populations might contribute to the tumor development such as metastasis via the resistance to apoptotic stimuli.
Insights
Cancer stem cells in sarcomas exhibit self-renewal and tumorigenicity. These cells resist apoptosis and senescence, potentially driving tumor development and metastasis.
Area of Science:
- Oncology
- Cancer Biology
- Stem Cell Research
Background:
- Cancer stem cells (CSCs) are implicated in the pathogenesis of various cancers, including solid tumors.
- Identifying CSCs is crucial for understanding tumor development and devising targeted therapies.
Purpose of the Study:
- To characterize sphere-colony forming cells from rat osteosarcoma and malignant fibrous histiocytoma cell lines.
- To investigate the stem-like properties and tumorigenic potential of these cells.
Main Methods:
- Culturing cells under anchorage-independent, serum-starved conditions to form spheres.
- Assessing self-renewal capacity and gene expression (STAT3, Bmi1, p16INK4a, p19ARF).
- Evaluating tumorigenicity and metastatic potential through in vivo inoculation into syngeneic rats.
Main Results:
- Both cell lines formed sphere-colonies, indicating clonal expansion under stem cell-selective conditions.
- Sphere cells demonstrated self-renewal and expressed stem cell markers STAT3 and Bmi1.
- A decrease in INK4a/ARF locus genes (p16INK4a, p19ARF) was observed, potentially conferring resistance to senescence and apoptosis.
- In vivo studies revealed significant tumorigenicity and metastatic potential of these sphere cells.
Conclusions:
- Sphere-colony forming cells in rat osteosarcoma and malignant fibrous histiocytoma exhibit cancer stem cell-like properties.
- These CSCs possess self-renewal, tumorigenicity, and metastatic potential.
- Reduced expression of tumor suppressor genes may contribute to the resistance of CSCs to apoptosis and senescence, facilitating tumor progression.
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