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Cloning and characterization of human cDNAs encoding a protein with high homology to rat intestinal development
1Institute of Pathology, Charité, Humboldt University Berlin, Germany. lage@rz.charite.hu-berlin.de
Abstract:
We constructed a lambda complementary DNA expression library from the mitoxantrone-resistant human gastric carcinoma cell line EPG85-257RNOV. The library was screened by differential hybridization (resistant cell line against non-resistant cell variant). By this procedure we found five independent cDNA clones representing one single gene that has much higher expression in the mitoxantrone-resistant cell line EPG85-257RNOV than in the non-resistant variant EPG85-257P. One of the cDNA clones (MXR7) contains a complete open reading frame (ORF) encoding a 580-amino acid polypeptide. Amino acid and nucleotide sequence analysis revealed that this gene codes the human variant of a rat intestinal development protein OCI-5.
Insights
Researchers identified a gene, MXR7, highly expressed in mitoxantrone-resistant human gastric cancer cells. This gene codes for a human variant of the rat intestinal development protein OCI-5, offering insights into drug resistance mechanisms.
Area of Science:
- Molecular Biology
- Cancer Research
- Genetics
Background:
- Drug resistance in cancer is a significant clinical challenge.
- Understanding the molecular basis of resistance is crucial for developing effective therapies.
- Human gastric carcinoma cell lines provide models for studying cancer progression and drug resistance.
Purpose of the Study:
- To identify genes overexpressed in mitoxantrone-resistant human gastric carcinoma cells.
- To characterize a novel gene associated with mitoxantrone resistance.
- To investigate the potential role of this gene in cancer drug resistance.
Main Methods:
- Construction of a complementary DNA (cDNA) expression library from a mitoxantrone-resistant human gastric carcinoma cell line (EPG85-257RNOV).
- Differential hybridization screening comparing resistant and non-resistant cell variants.
- Sequence analysis of isolated cDNA clones, including open reading frame (ORF) identification.
Main Results:
- Identification of five independent cDNA clones representing a single gene with significantly higher expression in the resistant cell line (EPG85-257RNOV) compared to the non-resistant variant (EPG85-257P).
- One clone, designated MXR7, contained a complete ORF encoding a 580-amino acid polypeptide.
- Sequence analysis revealed MXR7 as the human variant of the rat intestinal development protein OCI-5.
Conclusions:
- The gene MXR7 is overexpressed in mitoxantrone-resistant human gastric carcinoma cells.
- MXR7 represents the human homolog of the rat intestinal development protein OCI-5.
- This finding suggests a potential role for MXR7/OCI-5 in the development of mitoxantrone resistance in gastric cancer.