A transgenic mouse model for early prostate metastasis to lymph nodes

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Recurrent, metastatic prostate cancer is the lethal form of the disease, often occurring after androgen-deprivation therapy failure.
• The genetic underpinnings and timing of prostate cancer metastasis remain poorly understood.
• Loss of metastasis suppressors SSeCKS/Gravin/AKAP12 (Akap12) or Rb individually causes prostatic hyperplasia.

Purpose of the Study:

• To investigate the role of combined Akap12 and Rb gene loss in prostate cancer development and metastasis.
• To determine if metastasis is an early or late event in prostate cancer progression.
• To identify potential cellular origins of lymph node metastases.

Main Methods:

• Genetic manipulation of Akap12 and Rb genes in mouse models.
• Histopathological analysis of prostate tissues to assess lesion development.
• Immunohistochemical staining to identify specific cell markers (p63, cytokeratin 5/8/14, androgen receptor) in tumor cells and metastases.

Main Results:

• Combined Akap12 and Rb loss induced prostatic intraepithelial neoplasia (PIN) that did not progress to malignancy within 18 months.
• A significant percentage (83%) of mice with PIN lesions showed metastases to draining lymph nodes.
• Metastatic cells expressed markers of both basal and luminal prostate epithelial cells, with a notable increase in p63/AR-positive, cytokeratin 5-negative basal cells within PIN lesions.

Conclusions:

• Akap12 acts as a suppressor of oncogenic proliferation and early metastatic spread in prostate cancer, particularly in the context of Rb loss.
• Prostate intraepithelial neoplasia (PIN) lesions with combined Akap12 and Rb loss can be a source of early lymph node metastasis.
• Transitional basal-luminal prostate tumor cells may represent the cell type responsible for early metastatic dissemination.