Aberrant estrogen receptor alpha expression correlates with hepatocellular carcinoma metastasis and its mechanisms

Metastasis one of the obstacles before poor prognosis of hepatocellular carcinoma (HCC) is improved. Estrogen receptor alpha (ERalpha) plays an important role in the development and progression of HCC. However, the molecular mechanism of ERalpha in mediating HCC metastasis is still unclear. The aim of the present study was to detect aberrant ERalpha expression in HCC and elucidate its possible mechanisms in HCC metastasis.

We detected expression of ERalpha, phospho-estrogen receptor alpha (p-ERalpha), nuclear factor kappa B (NF-kappaB) p65 and Matrix metalloproteinase-9 (MMP-9) between HCC tissues with portal vein tumor thrombus (PVTT) and those without PVTT by immunohistochemical method. Moreover, the expression of above parameters was also determined in HCC cells of different metastatic potential by using immunocytochemical and reverse transcriptase-polymerase chain reaction (RT-PCR) methods.

The expression of ERalpha and p-ERalpha was lower in HCC with PVTT than those without PVTT. Meanwhile, the expression pattern of above parameters was also similar in HCC cells of different metastatic potential, whereas, the expression of NF-kappaB p65 and MMP-9 was higher in HCC with PVTT than those without PVTT. The expression of NF-kappaB p65 and MMP-9 in HCC cells was also analogous to the tissues.

These results demonstrated that expression of ERalpha, p-ERalpha, NF-kappaB p65 and MMP-9 correlated with invasion and metastasis in HCC. The mechanism of HCC metastasis may mediate through cross-talk between the NF-KB and ER signaling pathways. Meanwhile, ERa regulated MMP-9 through NF-kappaB indirectly.