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Human ovarian cancers express somatostatin receptors
1Endocrine, Polypeptide, and Cancer Institute, Veterans Affairs Medical Center, Department of Medicine, Tulane University School of Medicine, New Orleans, Louisiana 70112-2699, USA.
Abstract:
Characteristics of receptors for somatostatin (SST) analog RC-160 on 17 surgical specimens of human epithelial ovarian cancer and two human ovarian cancer lines were determined by ligand competition assays. The expression of mRNA for four SST receptor subtypes (sst1, sst2A, sst3 and sst5) was investigated by RT-PCR. Thirteen of 17 specimens (76%) exhibited high affinity binding sites for RC-160 with Kd = 6.55 nmol/L and a Bmax = 575.4 fmol/mg membrane protein. Specific receptors for RC-160 were also found in xenografts of OV-1063 and UCI-107 human ovarian cancer lines. The mRNA for sst1 was detected in 65% of the ovarian cancer specimens, while the incidence of sst2A, sst3 and sst5 was 65%, 41% and 24%, respectively. Both ovarian cancer cell lines also expressed mRNA for these four subtypes. The presence of these SST receptor subtypes in human ovarian cancers allows the use of SST analogs and their radionuclide and cytotoxic derivatives for the diagnosis and treatment of this malignancy.
Insights
Human ovarian cancers express somatostatin (SST) receptors, suggesting SST analogs can be used for diagnosis and treatment. These findings highlight potential new therapeutic strategies for ovarian cancer patients.
Area of Science:
- Oncology
- Endocrinology
- Molecular Biology
Background:
- Ovarian cancer remains a significant health challenge with limited treatment options.
- Somatostatin (SST) receptors are implicated in various cellular functions and cancer pathways.
- SST analogs have shown therapeutic potential in other malignancies.
Purpose of the Study:
- To characterize somatostatin (SST) receptor expression in human epithelial ovarian cancer.
- To investigate the presence and subtypes of SST receptors (sst1, sst2A, sst3, sst5) in ovarian tumors and cell lines.
- To assess the potential of SST analogs for ovarian cancer diagnosis and treatment.
Main Methods:
- Ligand competition assays were used to determine the characteristics of SST receptors.
- Reverse transcription-polymerase chain reaction (RT-PCR) was employed to detect mRNA expression of four SST receptor subtypes.
- Analysis was performed on 17 surgical specimens of human epithelial ovarian cancer and two ovarian cancer cell lines (OV-1063, UCI-107).
Main Results:
- High-affinity binding sites for the SST analog RC-160 were found in 76% of ovarian cancer specimens.
- Specific receptors for RC-160 were also identified in xenografts of ovarian cancer cell lines.
- mRNA for sst1, sst2A, sst3, and sst5 receptors was detected in varying percentages of tumor specimens and in both ovarian cancer cell lines.
Conclusions:
- The presence of multiple somatostatin receptor subtypes in human ovarian cancers is confirmed.
- These findings support the potential use of somatostatin analogs for diagnostic and therapeutic applications in ovarian cancer.
- SST analogs and their derivatives offer promising avenues for targeted therapy and diagnosis in ovarian malignancies.