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Updated: Oct 29, 2026
Discovery of Driver Genes in Colorectal HT29-derived Cancer Stem-Like Tumorspheres
Published on: July 22, 2020
Screening and identification of down-regulated genes in colorectal carcinoma by subtractive hybridization: a method
Objective:
To search for new putative tumor suppressor genes in colorectal carcinoma.
Methods:
Subtractive hybridization technologies were applied to screen and select genes, the expression of which was down-regulated in colorectal carcinoma. mRNAs uniquely expressed in normal cells but not in colorectal carcinoma were recovered as cDNA (sub-cDNA) after two rounds of subtractive hybridization with mRNA prepared from colorectal carcinoma. The sub-cDNAs were then used as probes to screen a normal human colon cDNA library constructed in lambda-Zap II phage. The DNAs of positive clones were in vivo excised, and partial DNA sequences were analyzed and compared with DNA sequence database Genbank.
Results:
A total of 46 different clones with an average of about 1 kilobases in transcript size was recovered. Among these 46 down-regulated genes in colorectal carcinoma were genes encoding immunoglobulin (n = 32), 40-kDa keratin intermediate filamentous protein or IFP (n = 1), major histocompatibility complex-related protein (n = 1), unrelated structural proteins (n = 10) and gene products yet to be identified (n = 2). RNA dotblot hybridizations confirmed that all 46 clones contained genes that were down-regulated and have not been reported before in colorectal carcinoma.
Conclusion:
The results of this study suggested that the 46 clones were down-regulated in colorectal carcinoma, they should be further studied as new putative tumor suppressor genes and could be used as new tumor markers of colorectal carcinoma.
Insights
Researchers identified 46 novel genes downregulated in colorectal carcinoma using subtractive hybridization. These genes are potential tumor suppressors and could serve as new biomarkers for colorectal cancer detection.
Area of Science:
- Molecular Biology
- Oncology
- Genetics
Background:
- Colorectal carcinoma is a significant global health concern.
- Identifying novel tumor suppressor genes is crucial for understanding cancer development and treatment.
- Gene expression alterations are key indicators in cancer research.
Purpose of the Study:
- To discover new putative tumor suppressor genes in colorectal carcinoma.
- To identify genes with significantly downregulated expression in colorectal cancer tissues compared to normal tissues.
Main Methods:
- Subtractive hybridization techniques were employed to isolate differentially expressed genes.
- Messenger RNAs (mRNAs) uniquely present in normal colon cells were identified.
- A normal human colon cDNA library was screened using complementary DNAs (cDNAs) from downregulated genes.
Main Results:
- Forty-six distinct clones representing downregulated genes were successfully recovered.
- Identified genes included those encoding immunoglobulins, keratin intermediate filamentous protein (IFP), and major histocompatibility complex-related proteins.
- RNA dotblot hybridizations confirmed the downregulation of all 46 identified genes in colorectal carcinoma, with no prior reports in this cancer type.
Conclusions:
- The 46 identified clones exhibit downregulated expression in colorectal carcinoma.
- These downregulated genes represent potential novel tumor suppressor genes.
- The identified genes hold promise as new tumor markers for colorectal carcinoma diagnosis and monitoring.
