Expression of cancer-testis antigens in hepatocellular carcinoma

AIM: To investigate the expression of cancer-testis (CT) anigens MAGE-1, SSX-1 ,CTp11 and HCA587 genes in hepatocellular carcinoma (HCC) and the possibility of applying these antigens as targets for specific immunotherapy for HCC. METHODS: Expression levels of MAGE-1, SSX-1, CTp11 and HCA587mRNA were detected with reverse transcription polymerase chain reaction (RT-PCR) in HCC tissues and corresponding adjacent non-cancerous tissues from 105 HCC patients, 40 samples of cirrhosis and normal liver tissues.Genes of five samples with positive PCR results were sequenced.RESULTS: Of 105 HCC tissues, MAGE1, SSX-1 ,CTp11 and HCA587mRNA expressions were detectable in 75.2%(79/105),72.4%(76/105), 62.9%(66/105) and 56.2%(59/105) of HCC samples, respectively. About 93.3%(98/105), 72.4%(76/105),48.6%(51/105) and 37.1%(39/105) of HCC tissues positively expressed at least one, two, three, and four members of CT antigens, respectively. Conversely, only SSX-1 could be detectable in 2.9%(3/105) of the corresponding adjacent non-HCC tissues in which no metastatic lesion was found.Of the latter 3 patients, biopsy samples far from tumor were obtained in 2 patients and RT-PCR indicated no expression of SSX-1 mRNA in these two samples. In addition,none of 40 samples of cirrhotic and normal liver tissues expressed CT antigen gene mRNA. DNA sequences confirmed that the RT-PCR products were true target cDNA. No relationship was found between expression of CT antigens and clinico pathological indicators such as age,gender, tumor size, degree of tumor differentiation, serum α-fetoprotein level and infection of hepatitis B virus or hepatitis C virus (P＞0.05).CONCLUSION: CT antigens genes (MAGE-1, SSX-1, CTp11 and HCA587) are expressed with high percentage and specificity in HCC and their products are promising targets for antigen-specific immunotherapy of HCC. High frequent co-expression of multiple members of CT antigens in HCC provides possibility of polyvalent vaccinations for HCC.

A novel,rapid strategy to form dendritomas from human dendritic cells and hepatocellular carcinoma cell line HCCLM3 cells using mature dendritic cells derived from human peripheral blood CD14+monocytes within 48 hours of in vitro culture

AIM: Dendritomas formed by fusing cancer cells to dendritic cells have already been applied to clinical treatment trial of several types of cancers. Dendritic cells for the fusion in most trials and experiments were from blood monocytes in standard 7-d protocol culture, which requires 5-7 d of culture with granulocyte-macrophage-colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4), followed by 2-3 d of activation with a combination of proinflammatory mediators such as tumor necrosis factorα (TNFα), interleukin-1β (IL-1β), interleukin-6 (IL-6) and prostaglandin E2 (PGE2).One study showed that mature monocyte-derived dendritic cells could be obtained within 48 h of in vitro culture with the same protocol as standard 7-d culture and referred to as FastDCs. Here we aimed to fuse human hepatocellular carcinoma cell line HCCLM3 cells with mature monocytederived dendritic cells within 48 h of in vitro culture (FastDC).METHODS: HCCLM3 cells were cultured in RPMI 1640 with 150 mL/L fetal calf serum (FCS). CD14+monocytes from healthy human peripheral blood were purified with MACS CD14 isolation kit and cultured in six-well plates in fresh complete DC medium containing RPMI-1640, 20 mL/L heat inactivated human AB serum, 2 mmol/1 L-glutamine,100 μg/mL gentamicin, 1000 U/mL GM-CSF and 500 U/mL IL-4 for 24 h, then proinflammatory mediators such as TNFα(1000 U/mL), IL-1β (10 ng/mL), IL-6 (10 ng/mL) and PGE2(1 μg/mL) were supplemented for another 24 h, and thus mature FastDCs were generated. HCCLM3 cells and FastDCs were labeled with red fluorescent dye PKH26-GL and green fluorescent dye PKH67-GL respectively. After the red fluorescent-stained HCCLM3 cells were irradiated with 50 Gy, FastDCs and irradiated HCCLM3 cells were fused in 500 mL/1 polyethylene glycol(PEG)+100 mL/L dimethyl sulfoxide (DMSO) to generate novel dendritornas. The FastDCs and novel dendritomas were immunostained with antiCD80, anti-CD86, anti-CD83, anti-HLA-DR mAbs and analyzed by fluorescence-activated cell sorting (FACS).Novel dendritomas were nucleus-stained with Hoechst 33258 and analyzed by confocal laser scanning microscopy.RESULTS: Mature FastDCs with highly expressed surface markers CD80, CD86, CD83 and HLA-DR were generated within 48 h in vitro. Novel dendritomas with dual red-green fluorescence were constructed fast and successfully, and FACS analysis showed that the fusion efficiency was 24.27% and the novel dendritomas expressed the same activation markers as FastDCs. Confocal laser scanning microscopy analysis showed representative images of dendritomas.CONCLUSION: Dendritomas can be formed fast with mature FastDCs from healthy human peripheral blood monocytes (PBMC) by incubation with GM-CSF and IL-4 for 24 h and by activation with proinflammatory mediators for an additional period of 24 h. Owing to shorter time required for in vitro DCs development, the generation of these novel dendritomas reduced labor and cost. This rapid method for formation of dendritomas may represent a new strategy for immunotherapy of hepatocellular carcinoma.