RGB-Marking to Identify Patterns of Selection and Neutral Evolution in Human Osteosarcoma Models

Area of Science:

• Oncology
• Genetics
• Cancer Biology

Background:

• Osteosarcoma (OS) is an aggressive bone cancer with complex genetics and a tendency to metastasize.
• Previous genetic studies suggest complex clonal evolution in OS, but limitations exist in next-generation sequencing (NGS) data analysis.
• Experimental models are crucial for validating hypotheses on OS clonal evolution.

Purpose of the Study:

• To investigate tumor heterogeneity and clonal dynamics in osteosarcoma using experimental models.
• To validate the hypothesis of clonal evolution in OS through in vivo studies.
• To analyze the impact of selective forces on OS tumor growth and composition.

Main Methods:

• Generation of colorimetric red, green, blue (RGB)-marked osteosarcoma cell lines (murine, canine, human) using lentiviral LeGO-vectors.
• In vivo study of tumor clonal dynamics in immunodeficient NOD.Cg-Prkdcscid-Il2rgtm1Wjl/SzJ (NSG) mice.
• Analysis of tumor clonal composition using confocal microscopy, flow cytometry, and supervised/unsupervised clonal analyses based on colorimetric labels.

Main Results:

• Consistent reduction in clonal composition of RGB-marked osteosarcoma tumors observed.
• Evident clonal selection identified during the first passage in immunodeficient mice.
• Demonstrated that osteosarcoma can exhibit neutral growth, characterized by the coexistence of different tumor sub-clones.

Conclusions:

• Experimental models are essential for rigorously testing hypotheses regarding osteosarcoma clonal evolution.
• Clonal selection and neutral growth models are relevant to understanding osteosarcoma progression.
• The study underscores the importance of validating findings from genetic studies in experimental settings.