Local expression of interferon-alpha and interferon receptors in cervical intraepithelial neoplasia

Abstract

Purpose: The present study evaluated mRNA expression of interferon-alpha (IFN-alpha), IFN-alpha receptor subunits (IFNAR-1 and IFNAR-2) and an IFN-stimulated gene encoding the enzyme 2',5'-oligoadenylate synthetase (2'5'OAS) in biopsies on patients with varying grades of cervical intraepithelial neoplasia (CIN I, II and III).

Methods: Uterine cervix biopsies were collected from women with CIN I, II and III (n = 28) and controls without CIN lesions or human papilloma virus (HPV) infection (n = 17). The presence of high and low-risk HPV DNA was determined using hybrid capture. The mRNA levels of IFNAR-1, IFNAR-2, IFN-alpha and 2'5'OAS were determined by RT-PCR with specific primers.

Results: The control group exhibited a greater frequency of IFNAR-1 expression (10/17; 58.3%) than the CIN samples (4/28; 14.2%) (P = 0.0018), while, the expression of IFNAR-2 was also greater in the control samples (11/17; 64.7%) than in the patients with lesions (2/28; 7.1%) (P = 0.0018). Importantly, simultaneous expression of both receptors was observed only in the control group (8/17; 47.0%) (P = 0.0001). Among the CIN samples, there was one case of low expression of mRNA of IFNAR-1 and IFNAR-2. IFN-alpha was present in 14.2% (4/28) of the CIN samples but was not expressed in the control group. mRNA 2'5'OAS were expressed in 28.5% (8/28) of the CIN samples and 11.7% (2/17) of the control samples (not statistically significant). Fifty percent (14/28) of the CIN samples were positive for HPV DNA.

Conclusions: Cervical biopsy samples from control women or those without neoplasia or HPV infection displayed higher IFN-alpha receptor expression than those with CIN, while simultaneous expression of both IFN-alpha receptor subunits was found only in the control group. There was no significant difference in mRNA expression of IFN-alpha and 2'5'OAS between the control and CIN groups. Then we concluded that the samples obtained from patients with CIN present low levels of the IFN-alpha receptor mRNA.

Fig. 1

β-actin expression. a, b Column 1 50 bp DNA marker, columns 2–10 control samples. c, d, e Column 1 50 bp DNA marker, columns 2–10 CIN samples

Fig. 2

Reduced expression of IFNAR-1 in CIN cells. Photograph of a 10% polyacrylamide gel, stained with silver nitrate for analysis of the PCR products from IFNAR-1. a, b Column 1 50 bp DNA marker, columns 2–10 show the presence of the fragment (500 bp) in ten samples from the control group. c, d Column 1 50 bp DNA marker, columns 2–10 CIN samples, with receptor expression in four of them

Fig. 3

Reduced expression of IFNAR-2 in CIN cells. The synthesis of mRNA for IFNAR-2 in biopsies on patient with CIN or control group patients was analyzed by means of RT-PCR. a, b Electrophoresis gels showing the PCR product of the receptor from the control group: column 1 50 bp DNA marker, columns 2–10 contain the fragment (105 bp) in 11 samples from the control group. c Column 1 50 bp DNA marker, columns 2–10 contain the receptor in two CIN samples

Fig. 4

RT-PCR detection of IFN-α in CIN cells. a, b Column 1 50 bp DNA marker, columns 2–10 show the presence of the fragment (316 bp) in four samples from the CIN group. None of the control group samples expressed IFN-α (data not shown)

Fig. 5

RT-PCR detection of the 2′5′OAS enzyme gene in CIN cells. a, b Column 1 50 bp DNA marker, columns 2–10 control samples showing presence of the expected fragment (69 bp) in two samples. c, d, e, Column 1 50 bp DNA marker, columns 2–10 demonstrate the presence of the fragment in eight samples from the CIN group