RESUMEN
OBJECTIVE: To investigate potential human leucocyte antigen (HLA)-A2-restricted epitope peptides of glypican-3 (GPC3) and determine the cytotoxicity of peptide-specific cytotoxic T lymphocytes (CTLs) against hepatocellular carcinoma (HCC) cells. METHODS: The potential HLA-A*0201-restricted GPC3 peptides were screened using computer algorithms, T2 cell-binding affinity and stability of peptide/HLA-A*0201 complex assay. The peptide-specific CTLs were generated and their cytotoxicity against GPC3+ SMMC 7721 and HepG2 cells was detected using IFN-γ based enzyme-linked immunospot and lactate dehydrogenase release assays in vitro. RESULTS: A total of six peptides were identified for bindings to HAL-A2 and the GPC3 522-530 and GPC3 229-237 peptides with HLA-A*0201 molecules displayed high binding affinity and stability. The CTLs induced by the GPC3 522-530 or positive control GPC3 144-152 peptide responded to the peptide by producing IFN-γ, which were abrogated by treatment with anti-HLA-A2 antibody. The GPC3 522-530-specific CTLs responded to and killed SMMC 7721 and HepG2 cells, instead of GPC3-silenced SMMC 7721 or HepG2 cells. GPC3 522-530-specific CTLs response to HCC cells was blocked by anti-HLA-A2 antibody. CONCLUSIONS: The GPC3 522-530 peptide contains antigen-determinant and its specific CTLs can effectively kill HCC in a HLA-A2-restricted and peptide-dependent manner. Our findings suggest that this peptide may be valuable for development of therapeutic vaccine.
RESUMEN
PURPOSE: Anti-angiogenic agents have shown promise for treating advanced hepatocellular carcinoma (HCC), and the primary mechanism of low-dose metronomic chemotherapy using traditional cytotoxic drugs is anti-angiogenic. This study evaluated the efficacy of metronomic capecitabine and thalidomide after cool-tip radiofrequency ablation (RFA), relative to RFA alone, for treating patients with HCC. METHODS AND MATERIALS: Patients with HCC were randomly apportioned to a test group (n = 22) receiving metronomic chemotherapy with capecitabine and thalidomide after RFA, or a control group (n = 28) receiving RFA only. Serum circulating endothelial cells (CECs) and vascular endothelial growth factor (VEGF) were measured in all patients before and 1 month after RFA treatment. Enhanced computed tomography or ultrasound imaging was performed to evaluate efficacy during 12 months of follow-up. The treatment groups were further stratified as HCC within or outside the Milan criteria for transplantation. RESULTS: One month post-treatment, the tumour response rate (TRR), including complete response and partial response rate, of the test and control groups was statistically similar. At 12 months, the TRR of the test group (68.2%) was significantly higher than that of the control group (35.7%). In the test group, the TRR of patients whose tumour burdens were outside the Milan criteria was significantly higher than that of the control group. One month post-treatment, CECs and VEGF levels of the test group were significantly lower than baseline, while those of the control group were significantly higher. At the end of the 12-month follow-up, there was a progression-free survival (PFS) benefit of 2 months in the test group. CONCLUSION: Metronomic capecitabine and thalidomide after RFA significantly reduced recurrence of HCC and extended PFS, especially for HCC outside the Milan criteria, perhaps via reduction of serum CECs and VEGF levels and inhibition of tumour angiogenesis.