EGFR Activation is Suppressed by High Doses of Folic Acid in HPV Negative Cervical Cancer Cells

Abstract

Cervical cancer is one of the leading causes of death due to cancer in women. Human Papilloma Virus infection is the primary risk factor for developing cervical cancer, however very little is known about HPV negative cervical cancers. Folate fortification of flour for prevention of neural tube defects has been mandatory in North America since 1998; and folate supplementation is recommended during pregnancy. Folate fortification is not mandated in all countries, however, due to concerns about possible adverse effects on cancer incidence or prognosis. There is evidence that folate intake can reduce risk of developing tumors but other contradictory studies indicate that supraphysiologic doses of folate can actually lead to disease progression. Folate receptor alpha is known to be expressed in many cancer cell lines, including HPV positive cervical cancer. There is some evidence that folic acid can promote methylation of the EGFR, leading to a decrease in EGFR expression, and that EGFR might be active in some HPV positive cervical cancers. The purpose of this study is to determine if EGFR plays a role in HPV negative cervical cancer cell growth, and the effects of folic acid on EGFR protein expression and activation. Two HPV negative cervical cancer cell lines were used for this study: C33A and DoTc2‐4510. High doses of folic acid caused a decrease in both C33A and DoTc cell proliferation. Interestingly, qPCR and western blotting analysis indicate that only the DoTc2‐4510 cells expressed EGFR. The DoTc2‐4510 cells were sensitive to the EGFR inhibitor, gefinitib, with an IC50 of 0.01 uM. There was no change in EGFR expression upon folic acid treatment, but interestingly high doses of folic acid did inhibit EGFR activation. Taken together this data indicates that EGFR may be a target for a subset of HPV negative cervical cancers, and that high doses of folic acid may help prevent EGFR positive HPV negative cervical cancer cell growth.