Estrogen Receptor-α's Role in Squamous Cell Carcinoma Irradiated with Radiation

Oral cancer is one of the most common malignant tumors claiming the life of one person each hour. Diagnosis at a more advanced stage, complexity of the head and neck region, high rate of recurrence and aggressive metastasis account for the unfavorable clinical outcome. 

Objective:

Our objective in this study is i) to examine whether estrogen receptor- α (ER- α ) is expressed in oral squamous cell carcinoma  and ii) whether radiation treatment is partly responsible for clonal selection of tumor cells that survive after treatment.  The overall goal is to validate whether ER- α is a critical target to prevent tumor recurrence/metastasis after treatment.   

Method:

 Cells from oral squamous cell carcinoma of human tongue (SCC-4) were either untreated or exposed to radiation (2 and 10 Gy) at a dose rate of 0.98 Gy/min.  The viability of the cells after treatment monitored with Trypan Blue Dye exclusion method showed greater than 90% cell viability.  The cells were harvested at 1, 2, 6, 12 and 24 and total protein was estimated.   Western blots of whole cell extract (100 ug of protein) were performed to examine the expression levels of ER-α.

Result:

Westernblot analysis showed an increased expression of ER- α in SCC-4 cells compared to normal cells of epithelial origin.  Further, a dose-dependent increase in the level of ER-α expression was observed in SCC-4 cells after radiation exposure.  The rapid expression of ER-α was at maximum level at 2 hours.  However, there was no difference in ER-α expression at the later time point (24h). Further experiments are carried out to imply the important role of ER-α in tumor recurrence after radiation at therapeutic doses used in the patient treatment.  

Conclusion:

The promising results indicate that targeting ER-a may provide an effective treatment outcome in preventing tumor recurrence after treatment.