Serum LAPTM4B-35 protein as a novel diagnostic marker for hepatocellular carcinoma / 北京大学学报(医学版)

OBJECTIVE@#LAPTM4B-35 protein is one of the isoforms that are encoded by a cancer driver gene, LAPTM4B. This gene was primarily found and identified in our lab of Peking University School of Basic Medical Sciences. The LAPTM4B-35 protein and its encoded mRNA are significantly over-expressed in a variety of cancers, such as hepatocellular carcinoma (HCC), lung cancers (including non small-cell lung cancer and small-cell lung cancer), stomach cancer, colorectal carcinoma, pancreatic cancer, gallbladder cancer, cholangiocarcinoma, breast cancer, prostate cancer, ovarian cancer, cervical cancer, endometrial cancer, and so on. It has firmly demonstrated through lab experiments either in vivo or in vitro, as well as clinical studies that the over-expression of LAPTM4B-35 can promote cancer growth, metastasis, and multidrug resistance. Specially, the expressive level of LAPTM4B-35 is associa-ted with recurrence of HCC. The aim of this study is to identify the release of LAPTM4B-35 protein from hepatocellular carcinoma into blood of HCC patients and into the medium of cultured HCC cells, and to identify its possible form of LAPTM4B-35 protein existed in blood and cell culture medium, as well as to explore the possibility of LAPTM4B-35 protein as a novel HCC biomarker for diagnosis of HCC and prognosis of HCC patients.@*METHODS@#Immunobloting (Western blot) and enzyme-linked immunosorbent assay (ELISA) were used for identification of LAPTM4B-35 protein in the blood of HCC patients and normal individuals. Ultrafiltration and ultracentrifugation were used to isolate and purify exosomes from the culture medium of HCC cells.@*RESULTS@#LAPTM4B-35 protein existed in the blood from HCC patients and normal donors that were demonstrated through Western blot and ELISA. LAPTM4B-35 was also released into the culture medium of HCC cells in the form of exosomes. Preliminary experiments showed that the average and the median of LAPTM4B-35 protein level in the blood of HCC patients (n=43) were both significantly higher than that in the blood of normal donors (n=33) through sandwich ELISA.@*CONCLUSION@#It is promising that the LAPTM4B-35 protein which is released from HCC cells in the form of exosomes into their extraenvironment may be exploited as a novel cancer biomarker for HCC serological diagnosis.

Laminin and its alpha 6 integrin receptor in the regulation of human hepatocellular carcinoma cell phenotypes / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study the role of integrin alpha 6 in cell attachment, spread, survival/proliferation and differentiation of human hepatocellular carcinoma (HCC) BEL-7402 cells on various substrates by monoclonal antibody against the extracellular domain of alpha 6 subunit (IA6ED McAb).</p><p><b>METHODS</b>The effect of McAb on attachment and spread of BEL-7402 cells on LN or FN substrate was examined. MTT analysis was used to examine the cell survival/proliferation, gelatin zymography to the matrix metalloproteinases (MMPs) secreted by BEL-7402 cells, and microparticle immunoabsorbent kit to AFP secretion while the cells were cultured on LN-, FN- or Matrigel-coated substrates.</p><p><b>RESULTS</b>The cell attachment, spread and survival/proliferation were inhibited. Moreover importantly, the malignant cell dedifferentiation and abnormal differentiation on LN-coated substrate were also strongly inhibited by IA6ED McAb.</p><p><b>CONCLUSION</b>LN and integrin alpha 6 regulate human HCC cell phenotypes of survival/proliferation and differentiation. The phenotypes of dedifferentiation and abnormal differentiation can be reversed by blocking the interaction between integrin alpha 6 and LN using IA6ED McAb, which may lower metastatic potency of tumor cells.</p>