Human endometrial cells (EEC) are the main component of endometrial tissue and play a role in supporting the embryo during pregnancy. Normal EECs exhibit characteristic properties that can change with hormone sensitivity and the effects of steroid hormones. Cancerous EECs show uncontrolled proliferation, invasive properties, and apoptosis resistance. These cells are typically cultured with MEM medium and require 10% fetal bovine serum (FBS) and 1% penicillin/streptomycin. Additionally, these cells are sensitive to estrogen and progesterone receptors and show phenotype changes with hormone manipulation.
1. Advancement of Single-Cell Sequencing Technology:
In recent years, single-cell sequencing technology has revolutionized endometrial research. This technology has enabled us to understand the heterogeneity of endometrial cells and elucidate molecular mechanisms in disease development. To date, 7 fundamental research directions have been defined:
- Origin of endometrial cells and changes in pathological processes
- Endometrial functions related to reproductive health and infertility
- Endometrial dynamics during the menstrual cycle
- Endometrial stem cell properties and self-renewal capacity
- Molecular mechanisms of gynecological malignancies
- Endometrial receptivity and implantation process
- Creating a reference atlas for normal and pathological endometrium
2. PTEN/PIK3CA Gene Mutations:
PTEN and PIK3CA genes are frequently mutated in endometrial cancer cells. While the PTEN tumor suppressor gene negatively regulates the PI3K-AKT/mTOR signaling pathway, the PIK3CA oncogene activates this pathway. Mutations in these genes play a critical role in proliferation, apoptosis resistance, and metabolic changes of endometrial cancer cells. The PI3K-AKT/mTOR signaling pathway is responsible for cell growth, proliferation, and survival mechanisms.
3. Immunohistochemistry Phenotype Validation:
Immunohistochemistry methods are widely used for characterization of endometrial cells. The following steps are followed in this method:
- Embedding tissue samples in paraffin blocks
- Taking sections 4-5 micrometers thick
- Deparaffinization with xylene and alcohol series
- Heat or enzyme treatment for antigen retrieval
- Blocking endogenous peroxidase activity
- Primary antibody incubation
- Visualization with secondary antibody and chromogen
Common markers used in this procedure include estrogen receptor (ER), progesterone receptor (PR), Ki-67 (proliferation index), p53 (tumor suppressor protein), and vimentin (mesenchymal marker).
4. Molecular Markers:
Molecular markers associated with invasiveness and prognosis of endometrial cancer include POLE mutation, MMR (Mismatch Repair) deficiency, p53 abnormalities, and UBE2C (Ubiquitin-Conjugating Enzyme). POLE mutations are mutations in the exonuclease domain of DNA polymerase epsilon and are generally associated with better prognosis. MMR deficiency leads to microsatellite instability (MSI) and identifies patients who respond to immunotherapy. p53 abnormalities are associated with aggressive tumor behavior and poor prognosis. UBE2C is an enzyme that plays a role in cell cycle progression and tumor invasion.
5. Drug Screening and Disease Model Applications:
Endometrial cells are widely used for drug screening and disease model creation. Particularly the 3D endometrial cell model provides more physiological results by mimicking natural tissue architecture. The hEM3 cell line is a frequently used cell line in endometrial cancer research. EDS (Endometrial Derived Stromal) cells have been isolated for in vitro studies of endometrial stroma. The HEM15a cell line is the immortalized form of normal endometrial epithelial cells.
6. Rat Endometrial Organoids:
A research team from Shantou University has created and characterized uterine organoids using rat endometrial epithelial stem cells. These organoids not only show long-term stable proliferation capacity, but also preserve the glandular structure, cell polarity, and various functional properties of the endometrial epithelium. This model provides valuable information about the pathogenesis and pathophysiology of endometrial diseases, and also offers an efficient platform for drug screening and efficacy evaluation.
7. Molecular Markers and Clinical Applications:
Important molecular markers in endometrial research include HABP1 (Hyaluronan Binding Protein 1), CRABP2 (Cellular Retinoic Acid Binding Protein 2), TRAP1 (Tumor Necrosis Factor Receptor-Associated Protein 1), CAMSAP3 (Calmodulin-Regulated Spectrin-Associated Protein 3), PTEN (Phosphatase and Tensin Homolog), ARID1A (AT-Rich Interaction Domain 1A), PIK3CA (Phosphatidylinositol-4,5-Bisphosphate 3-Kinase Catalytic Subunit Alpha), and CAFs (Cancer-Associated Fibroblasts).
HABP1 is a protein that plays a role in cell migration and invasion. CRABP2 is involved in retinoic acid metabolism and exhibits tumor suppressor properties in endometrial cancer. TRAP1 is important in mitochondrial stress response and cell survival. CAMSAP3 plays a role in cytoskeleton organization. PTEN and PIK3CA are critically important in regulating the PI3K-AKT signaling pathway. ARID1A is a component of chromatin remodeling complexes and functions as a tumor suppressor. CAFs play an important role in the tumor microenvironment and support tumor progression.
Molecular classification of endometrial cancer is of great importance in terms of prognostic markers and targeted treatment strategies. UBE2C and CRABP2 stand out as prognostic markers in endometrial cancer. PI3K and MAPK signaling pathways play a critical role in endometrial cancer pathogenesis and are considered as therapeutic targets.
8. oHEM15a Cell Line:
oHEM15a cell line is derived from in situ endometrial stromal cells of endometriosis patients and established after immortalization treatment. This cell line exhibits adherent growth characteristics, expresses estrogen receptor (ER) and progesterone receptor (PR), and is suitable for investigating the pathological mechanisms and treatment methods of endometriosis. HEM15a cells maintain genomic stability across multiple passages, providing an important tool for disease models and drug screening.
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