Related Experiment Videos
Androgen receptor system in androgen-independent mouse tumor developed from androgen-dependent Shionogi carcinoma 115
Abstract:
An androgen-independent spindle-shaped cell tumor (NHD) formed from androgen-dependent medullary Shionogi carcinoma (SC115) in DS mice was examined. Although NHD tumors transplanted in female or male mice exhibited almost the same growth speed, the cytosol of this tumor was found to contain an androgen receptor which was similar in binding characteristics to SC115 tumor. Although significant amounts of specific binding sites for testosterone and 5 alpha-dihydrotestosterone were found in the SC115 nuclei as well as in the NHD nuclei shortly after the injection of 3H-testosterone, the androgens in the NHD nuclei disappeared rapidly. The androgen-independency of this tumor may be attributed to a rapid dissociation of the androgen-receptor complexes from NHD nuclei.
Insights
This study examined an androgen-independent tumor (NHD) derived from an androgen-dependent tumor (SC115). The NHD tumor
Area of Science:
- Oncology
- Endocrinology
- Molecular Biology
Background:
- Medullary Shionogi carcinoma (SC115) is an androgen-dependent tumor.
- An androgen-independent variant (NHD) can arise from SC115.
- Understanding the mechanisms of androgen independence is crucial for cancer treatment.
Purpose of the Study:
- To investigate the molecular mechanisms underlying the androgen independence of the NHD tumor.
- To compare the androgen receptor characteristics between SC115 and NHD tumors.
- To identify potential targets for therapeutic intervention in androgen-independent prostate cancers.
Main Methods:
- Tumorigenesis studies in DS mice.
- Androgen receptor binding assays in tumor cytosol and nuclei.
- Radioactive ligand binding studies using 3H-testosterone.
- Analysis of androgen-receptor complex dynamics in tumor nuclei.
Main Results:
- NHD tumors exhibited similar growth rates in both male and female mice, indicating androgen independence.
- Cytosolic androgen receptors in NHD tumors showed binding characteristics similar to SC115 tumors.
- While SC115 and NHD nuclei initially bound testosterone and 5α-dihydrotestosterone, androgens rapidly disappeared from NHD nuclei.
- This rapid clearance suggests a faster dissociation of androgen-receptor complexes from NHD nuclei.
Conclusions:
- The androgen independence of NHD tumors is likely due to the rapid dissociation of androgen-receptor complexes from the tumor cell nuclei.
- This finding provides insight into the mechanisms of resistance to androgen deprivation therapy in prostate cancer.
- Further research into nuclear androgen receptor dynamics may reveal new therapeutic strategies.