B 型肝炎病毒 X 蛋白質之探討：藉由調節淋巴毒素 α 和 β 的表現以促進肝癌細胞中異位類淋巴結構的生成

Abstract

B型肝炎病毒X蛋白質 (HBx) 是由B型肝炎病毒所編碼出來的一種多功能性蛋白質，與肝癌的形成有關。異位類淋巴結構 (ELSs) 是由B細胞和T 細胞所組成的淋巴集結體，常見於慢性發炎的部位。先前的研究指出肝細胞中的ELSs對於肝癌病患有較差的預後，再者，ELSs的形成與淋巴毒素 (LT)-β所驅動之非典型NF-κB訊息傳遞途徑的活化有關。為了瞭解HBx在晚期肝癌中形成ELSs所扮演的角色，我們將HBx基因分別利用轉染和感染的方式植入肝癌細胞株中，並以即時定量聚合酶連鎖反應和西方墨點法去鑑定LT家族與非典型NF-κB相關訊息的表達。研究結果顯示，在表現HBx的HA22T/VGH肝癌細胞株中，會增加LTα和LTβ的表現，並且透過活化非經典型NF-κB訊息傳遞路徑，促進下游效應因子─趨化因子CXCL12、CXCL13和CCL21的表達，吸引B細胞與T 細胞過來聚集。由我們的研究結果可知HBx亦具有調控ELSs形成的功能，此機制的明朗化將提供一種新型的免疫治療策略，治療由HBV誘導所形成之肝癌。

Hepatitis B virus X protein (HBx) is a multifunctional protein encoded by the hepatitis B virus that involved in hepatocarcinogenesis. Ectopic lymphoid-like structures (ELSs) are lymphoid aggregates mainly composed of B cells and T cells, frequently developed at sites of chronic inflammation. Hepatic ELSs indicates poor prognosis for hepatocellular carcinoma (HCC), which are associated with activation of the lymphotoxin (LT)-β-driven non-canonical NF-κB signaling pathway. To understand the role of HBx in ELSs formation in advanced HCC, we used HBx-transfected and HBx-infected HCC cell lines to identify the expression of LT family and non-canonical NF-κB signals by real-time PCR and western bloting. The data showed that HBx expression in HA22T/VGH cells up-regulated LTα, LTβ and their downstream effectors, the chemokines CXCL12, CXCL13 and CCL21 which are necessary for recruitment of B cells and T cells, through stimulating the non-canonical NF-κB signaling pathway. Our findings revealed that HBx also functioned as a regulator in ELSs formation, providing a possibility to develop a novel immunotherapeutic strategy for treating HBV-induced HCC.