8.2.3 Role of Oestrogen

• Oestrogen is primarily produced in the ovaries and placenta
• What is the definition of the genomic pathway in oestrogen action?

  Oestrogen binds to ER, which binds to DNA and regulates gene expression
• What signaling cascades are activated by oestrogen in the non-genomic pathway?

  MAPK and PI3K
• What are the specific DNA sequences that ERs bind to called?

  Oestrogen response elements
• Oestrogen binding to its receptor causes a conformational change that allows the DNA-binding domain to bind to EREs.


  True
• What type of receptors are oestrogen receptors (ERs)?

  Nuclear receptors
• Match the primary role of oestrogen with an example of its effects:

  Regulation of menstrual cycle ↔️ Breast development

  Secondary sexual characteristics ↔️ Fat distribution
• What happens to two ER molecules when oestrogen binds to them?

  They dimerize
• In breast cancer, oestrogen can act as a growth factor
• Oestrogen acts as a growth factor for cancer cells, stimulating their proliferation and cell cycle progression.
• Oestrogen's effects on cancer are uniform across all types of cancer.

  False
• ER-negative breast tumors respond well to SERMs.

  False
• Which signaling pathways are activated by oestrogen in its non-genomic effects?

  MAPK and PI3K
• The binding of ERs to EREs always initiates transcription of target genes.

  False
• What are the primary receptors to which oestrogen binds?

  Oestrogen receptors
• Why are specific DNA sequences of EREs important for oestrogen's action?

  Selective and tissue-specific effects
• Oestrogen-sensitive breast cancer cells rely on oestrogen for continued growth.


  True
• Oestrogen stimulates breast cancer cell proliferation through both genomic and non-genomic mechanisms.
• Aromatase inhibitors prevent oestrogen synthesis by blocking the enzyme aromatase.
• Oestrogen plays a critical role in regulating the menstrual cycle.


  True
• Steps in the genomic pathway of oestrogen action

  1️⃣ Oestrogen binds to ER in the cytoplasm

  2️⃣ ER-oestrogen complex translocates to the nucleus

  3️⃣ Complex binds to oestrogen response elements on DNA

  4️⃣ Regulates transcription of target genes
• The non-genomic pathway of oestrogen action involves changes in gene expression.

  False
• The specific DNA sequences of EREs determine which genes are regulated by oestrogen.


  True
• What role do the specific DNA sequences of EREs play in oestrogen's action?

  Tissue-specific actions
• The ligand-binding domain of the ER binds to oestrogen
• What are the two main pathways through which oestrogen exerts its effects?

  Genomic and non-genomic
• Steps in the binding of the ER-oestrogen complex to DNA

  1️⃣ Oestrogen binding

  2️⃣ Dimerization

  3️⃣ Translocation

  4️⃣ DNA binding

  5️⃣ Transcription regulation
• Which type of cancer is commonly associated with oestrogen as a growth factor?

  Breast cancer
• Oestrogen-blocking therapies, like SERMs, are effective for ER-negative breast cancer.

  False
• What are the two main mechanisms by which oestrogen stimulates breast cancer cell proliferation?

  Genomic and non-genomic
• What type of hormone is oestrogen?

  Steroid hormone
• Oestrogen receptors bind to DNA after forming an active complex.
• What are the two key domains of oestrogen receptors?

  DNA-binding and ligand-binding
• Oestrogen receptors are nuclear receptors.


  True
• Oestrogen promotes cell proliferation during the G1-S transition of the cell cycle.


  True
• Match the cancer type with the effect of oestrogen:

  Breast Cancer ↔️ Promotes cell growth

  Colon Cancer ↔️ May inhibit cell growth
• Match the type of oestrogen mechanism with its description:

  Genomic ↔️ ER complex binds to EREs

  Non-Genomic ↔️ Activates signaling cascades
• Oestrogen exerts its effects through two main mechanisms: genomic and non-genomic
• In the genomic pathway, oestrogen binds to the ligand-binding domain of the ER
• The ligand-binding domain of the ER is responsible for binding to oestrogen