Pharmacological effects of site specific conjugated anti-human epidermal growth factor receptor 2-antibody drug conjugate using unnatural amino acid technology / 北京大学学报(医学版)

OBJECTIVE@#To investigate inhibitory activities of a homogenous anti-human epidermal growth factor receptor 2 (HER2)-antibody drug conjugate (ADC) on the proliferation of nine tumor cell lines with different levels of HER2 expressions, and its activities on the tumor growth of five xenograft mouse models.@*METHODS@#The HER2 expression levels of BT-474, Calu-3, MCF-7, MDA-MB-231, MDA-MB-468, SK-BR-3, SK-OV-3, HCC1954, NCI-N87 tumor cell lines were measured using QIFI KIT. For the in vitro anti-proliferation assay, serial diluted anti-HER2-ADC, ado-trastuzumab emtansine, AS269, pAF-AS269 and paclitaxel were added to the seeded cells, and after 72 or 96 hours of incubation, the cell proliferation was analyzed. For the in vivo activity, 5-6 weeks old mice were inoculated with four HER2 positive tumor cell lines HCC1954, BT-474, SK-OV-3, NCI-N87 or one HER2 negative tumor cell line MDA-MB-468. Different amounts of anti-HER2-ADC, ado-trastuzumab emtansine, trastuzumab, paclitaxel and phosphate buffered saline control were injected after the tumor volume reached a certain size, then the tumor growth inhibition was analyzed.@*RESULTS@#The expression levels of the six high HER2-expression cell lines SK-OV-3, NCI-N87, SK-BR-3, Calu-3, HCC1954, BT-474 were between 430 000 to 800 000 receptors per cell, which were 50 times higher than those of the other three low HER2 expression tumor cell lines MDA-MB-231, MCF-7, MDA-MB-468. Anti-HER2-ADC had inhibition effects on cell lines with high level of HER2 expression in the in vitro anti-proliferation assay. The half maximal inhibitory concentrations of anti-HER2-ADC on SK-OV-3, NCI-N87, SK-BR-3, Calu-3, HCC1954, BT-474 tumor cell lines were 46 pmol/L, 17 pmol/L, 17 pmol/L, 161 pmol/L, 125 pmol/L, 50 pmol/L, respectively. Anti-HER2-ADC had a dose dependent antitumor activity in vivo in all the HER2 positive xenograft mouse models. In NCI-N87 xenograft tumor model, the same dose of anti-HER2-ADC showed better anti-tumor activity compared with trastuzumab and ado-trastuzumab emtansine, and its relative tumor proliferation rates were about 1/30 to 1/20 of the two. In HCC1954 xenograft tumor model, the complete regression of the tumor was observed. As expected, anti-HER2-ADC had no tumor inhibitory effects on MDA-MB-468 xenograft models with low HER2 expression. The antitumor activities of anti-HER2-ADC in HER2 positive xenograft tumor models were the same as or better than the activities of ado-trastuzumab emtansine.@*CONCLUSION@#The homogenous site-specific anti-HER2-ADC obtained using unnatural amino acid technology can inhibit the growth of high HER2-expression tumor cells with high potency both in vivo and in vitro.

Differential gene expression profiles of DNA repair genes in esophageal cancer cells after X-ray irradiation / 癌症

<p><b>BACKGROUND AND OBJECTIVE</b>Various factors affect the radioresistance of tumor cells, with unknown molecular mechanism(s). Many genes have been found to associate with the radioresistance of tumor cells, however, the precise mechanism of these genes have not been elucidated. This paper was to analyze the differential expressions of DNA repair genes in esophageal carcinoma cells at different time after X-ray irradiation, and to investigate the role of these DNA repair genes in radiation resistance.</p><p><b>METHODS</b>Esophageal cancer parental cells Seg-1 were treated with continuous 2 Gy of fractionated irradiation until the total dose reached 60 Gy to establish the radioresistant cell line Seg-1R. Total RNA was extracted from each cell line at 0, 8, and 24 h after irradiation. Illumine Human-6 V3 microarray was used to identify differentially expressed genes between parental and radioresistant cells. Ten genes involved in DNA repair were obtained and their expressions at different time points after irradiation were analyzed by Gene Ontology analysis.</p><p><b>RESULTS</b>Ten DNA repair associated genes were found to be differentially expressed. Three of these genes, SLK, HMGB1, and PMS1, were not only differentially expressed between parental and radioresistant cell lines, but also expressed differently at different time points after irradiation in the same cell line.</p><p><b>CONCLUSIONS</b>PMS1 may be an important factor involved in the mechanism of radioresistance of esophageal carcinoma cells.</p>

Identification of differentially expressed genes related to radioresistance of human esophageal cancer cells / 癌症

<p><b>BACKGROUND AND OBJECTIVE</b>Radioresistant cells in esophageal cancer is one of the important reasons for the local failure of radiotherapy. In recent years, some researchers used gene chip technology to screen the differentially expressed genes between parental and radioresistant human esophageal cancer cells. But there were some problems in these studies, for example comparing cells at only one time interval, and genetic background not matching. In this study, we selected 3 different pairs of parental and radioresistant human esophageal cancer cells, and compared the gene expression profiles by cDNA microarray at 3 time intervals to identify and analyze the differentially expressed genes between parental and radioresistant human esophageal cancer cells.</p><p><b>METHODS</b>We compared the gene expression profiles between parental cells (TE13, Seg-1, Kyse170) and radioresistant cells (TE13R, Seg-1R, Kyse170R) before, and at 8 h and 24 h after irradiation with a cDNA microarray consisting of 48 000 genes (Human Genome). We identified differentially expressed genes by Pathway and GO analyses, and verified the differentially expressed genes LEF1 and CTNNB1 by RT-PCR.</p><p><b>RESULTS</b>A total of 460, 451, and 397 differentially expressed genes were found before, and at 8 h and 24 h after irradiation. After Pathway and GO analyses, 14 differentially expressed genes, participating in cell growth, apoptosis, cell cycle regulation, gene repair and signal transmission, were selected to further research. LEF1 and CTNNB1 were verified by RT-PCR, and the results were consistent with those of cDNA microarray.</p><p><b>CONCLUSIONS</b>The WNT signal pathway may be an important pathway participating in the formation of radioresistance of esophageal cancer cells. LEF1 and CTNNB1 may be the important genes causing the esophageal cancer cell radioresistance.</p>