[Analysis of gene expression of ribonuclease inhibitor in human breast cancer tissue].

OBJECTIVE

Ribonuclease inhibitor (RI), which is rich in human placenta, is a multi-functional acidic glycoprotein. Our previous studies showed that the growth of some solid tumors (S180 sarcoma, Ca761 breast cancer, and H22 hepatoma) could be significantly inhibited by RI extracted and purified from human placenta. This study was designed to observe the change of RI gene expression in human breast cancer tissue.

METHODS

The expression level of RI mRNA was determined by reverse transcription-polymerase chain reaction (RT-PCR) and capillary electrophoresis (CE). The RI content was determined by Western blot analysis.

RESULTS

The electrophoretic stripes of the RT-PCR products of the breast cancer tissues were narrower and the plaques of Western blot of the breast cancer tissues were smaller compared with the control breast tissues. The peak altitude and width of capillary electrophoretic absorptive curve of the RT-PCR product of the breast cancer tissue were clearly smaller than that of the control breast tissue. The capillary electrophoresis integral values of the absorptive peak areas of RT-PCR product of the breast cancer tissue and the control breast tissue were (3.320+/-0.365)x10(6) and (4.385+/-0.880)x10(6), respectively. The comparison between two groups reveals a remarkably difference (P< 0.01).

CONCLUSIONS

The gene expression of RI is clearly down-regulated in human breast cancer tissue that the RI mRNA level is remarkably lower and RI content also reduces significantly in human breast cancer tissue.