Structure and function of 17beta-hydroxysteroid dehydrogenase type 1 and type 2

Area of Science:

• Biochemistry
• Endocrinology
• Molecular Biology

Background:

• 17beta-Hydroxysteroid dehydrogenases (17HSDs) regulate active steroid hormone levels.
• Isoenzymes exhibit distinct tissue distributions and functions in sex steroid metabolism.
• 17HSD1 promotes estradiol synthesis, while 17HSD2 inactivates it.

Purpose of the Study:

• To explore the role of 17HSD isoenzymes in estrogen metabolism and hormone action.
• To understand the structural and mechanistic basis of 17HSD1 activity.
• To evaluate 17HSD1 inhibition as a therapeutic strategy for estrogen-dependent cancers.

Main Methods:

• Biochemical assays to characterize 17HSD enzyme activities.
• Structural determination of human 17HSD1 to elucidate its estradiol binding pocket.
• Analysis of 17HSD isoenzyme expression in normal and malignant breast tissues.

Main Results:

• 17HSD1 activity is crucial for local estradiol production in breast tissue.
• 17HSD2 activity opposes 17HSD1 by converting estradiol to estrone.
• Preliminary data indicate differential expression of 17HSD1 and 17HSD2 in malignant versus non-malignant breast cells.
• The three-dimensional structure of 17HSD1 reveals its mechanism and estrogen specificity.

Conclusions:

• 17HSD isoenzymes play critical roles in modulating sex steroid hormone activity.
• Targeting 17HSD1 presents a viable therapeutic approach for estrogen-dependent breast cancer.
• Understanding 17HSD1 structure-function relationships can guide the development of specific inhibitors.