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Updated: Sep 20, 2026
Methods to Enable Spatial Transcriptomics of Bone Tissues
Published on: May 3, 2024
Molecular heterogeneity in human osteosarcoma demonstrated by enriched mRNAs isolated by directional tag PCR
Ole K Olstad1, Vigdis T Gautvik, Sjur Reppe
1Department of Medical Biochemistry, Norwegian Radium Hospital, 0310 N-Oslo, Norway. o.k.olstad@basalmed.uio.no
Abstract:
Directional tag PCR subtractive hybridization was applied to construct a cDNA library generated from three different human osteosarcoma (OS) target cell lines (OHS, SaOS-2 and KPDXM) from which normal osteoblast (NO) sequences were subtracted. After two consecutive subtractive steps more than 98% of the common mRNAs species were depleted, leading to effective enrichment of the remaining target sequences. After differential screening of 960 clones, 81 candidates were further studied by Northern blot analysis and 73 represented separate mRNA species. Fifty-three of these showed enriched mRNA levels, of which 36 represented known and 17 not previously published cDNAs or EST sequences. The mRNAs showed a 1.4- to 504-fold enrichment compared to the mRNA levels in NO cells. The known mRNAs are: Ribosomal protein S11, KSP-37, Tethering factor SEC34, FXYD6, Alpha enolase, G-s-alpha, GPR85, DAF, RPL35A, GIF, TAPA-1, ANAPC11, DCI, hsp27, MRPS7 homolog, eIF p110 subunit, DPH2L, HMG-14, FB1 protein, chondroitin-6-sulphonase, calgizzarin, RNA polymerase II subunit, RPL13A, DHS, gp96, HHP2, acidic ribosomal phosphoprotein P2, ANT-2, ARF1, AFG3L2, SKD3, phosphoglucoisomerase, GST pi, CKI gamma 2, DNA polymerase delta small subunit and TRAP delta. Sections of human osteosarcoma biopsies and a xenograft were studied by in situ analysis. Seven cDNAs highly expressed in Northern blot analysis were tested. Their in situ expression differed between the xenograft and human sections as did that of collagen I. In the xenograft made from one of the target cell lines (OHS), a fair to strong representation of 3 cloned mRNAs was observed while collagen I mRNA was not detectable. We conclude that the molecular heterogeneity of these tumors is considerable. These results ought to have implications for future work to describe phenotypic subtypes with the aim of improving the diagnosis of human osteosarcomas.
Insights
This study identified novel and known genes highly expressed in human osteosarcoma (OS) cell lines compared to normal cells. These findings reveal significant molecular heterogeneity in OS tumors, aiding in future diagnostic subtype classification.
Area of Science:
- Molecular Biology
- Oncology
- Genomics
Background:
- Osteosarcoma (OS) is a primary bone cancer with complex molecular characteristics.
- Understanding gene expression differences between OS and normal cells is crucial for diagnosis and treatment.
Purpose of the Study:
- To construct a cDNA library enriched for sequences specific to human osteosarcoma cell lines.
- To identify novel and known differentially expressed genes in OS.
Main Methods:
- Directional tag PCR subtractive hybridization was used to create a subtracted cDNA library.
- Differential screening and Northern blot analysis were performed on 960 clones.
- In situ analysis was conducted on human OS biopsies and xenografts.
Main Results:
- Over 98% of common mRNA species were depleted, enriching target OS sequences.
- 73 distinct mRNA species were identified, with 53 showing enriched levels.
- 17 novel cDNAs or EST sequences were discovered, alongside 36 known genes, showing 1.4- to 504-fold enrichment.
Conclusions:
- Significant molecular heterogeneity exists within osteosarcoma tumors.
- Identified genes and novel sequences provide insights into OS biology.
- These findings have implications for classifying OS phenotypic subtypes and improving diagnosis.
