Expression of LXR and regulation of glucose and fat metabolism in human cancers

在本研究中，我们检测了LXRα在人类癌细胞系和一些切除的人类肿瘤中的表达。免疫组织化学检测8株胃癌细胞株中有5株细胞表达LxRα，4株人胃癌细胞株、1株黑色素瘤细胞株和1株骨髓瘤细胞株均未表达LxRα。1例肺癌(n=55)、2例精原细胞瘤/无性细胞瘤(n=42)、2例胃癌(n=30)LXRα表达阳性。LXR amRNathree胃癌细胞株(KATOM、MKN28和MKN45)均表达LXRα基因。相应地。在MKN28细胞中检测到RXRα/β、PEARα、SREBP1c/1a的基因表达。这意味着至少在MKN28中已经建立了从LxRα-RxR-SREBP1c到PPARα的通路。IRNA抑制LxRα在MKN28细胞中的表达不会引起细胞形态和生长速度的改变。LXRα拮抗剂(T0901317)初步诱导MKN28细胞生长停滞。综上所述，LXRα在人类肿瘤中的表达是罕见的事件，但过表达LXRa可能是肿瘤治疗的一个靶点。

In the present research, we examined expression of LXR α in human cancer cell lines and in some resected human cancers.1. Expression of LXR α in human cancer cell linesImmunohistochemical examination revealed expression of LXR α in five cell lines among eight gastric cancer cell lines.Pancereatic cancer cell lines (n=4), one melanoma cell line and one myeloma cell line lacked LXR α LBD expression.2. Expression of LXR a in human cancersOne case in lung carcinoma (n=55), two cases in seminomas/dysgerminomas (n=42)and two cases in gastric carcinomas (n=30) showed positivity for LXR α.3. Expression of LXR amRNAThree gastric cancer cell lines examined (KATOM, MKN28 and MKN45)expressed LXR α mRNA. Accordingly. mRNA for RXRα/β,PEAR α, SREBP1c/la were detected in MKN28 cells. This implies that at least in MKN28, pathway from LXR α -RXR-SREBP1c to PPAR α has been established.4. Inhibition of LXR α expression by iRNA in MKN28 caused no morphological change and growth rate of the cells.5. Preliminarily, antagonist of LXR α (T0901317)induced growth retardation of MKN28 cells. In conclusion, expression of LXR α in human cancers is rare event but overexpressed LXR a might be a target of cancer therapy.