AIM: To investigate the effect of N-(4-hydrophenyl) retinamide (4-HPR), the derivative of retinoic acid, on inhibition of migration, invasion, cell growth, and induction of apoptosis in hepatocellular carcinoma cells ...AIM: To investigate the effect of N-(4-hydrophenyl) retinamide (4-HPR), the derivative of retinoic acid, on inhibition of migration, invasion, cell growth, and induction of apoptosis in hepatocellular carcinoma cells (HCCs) and malignant melanoma cells.METHODS: 4-HPR was chemically synthesized. Cellular migration and invasion were assayed by Borden chamber experiment. Cell growth was assayed by MTT chromometry.Apoptosis effect was measured using Hoechst 32258 staining and flow cytometry. Gene transfection was performed with lipofectamine.RESULTS: We observed that the migration of HCC and melanoma cells was significantly suppressed by 4-HPR and the migration cells were reduced to 58±5.03 (control 201±27.2, P＜0.05, n = 4) in SMMC 7721-k3 HCC, and to 254±25.04 (control 302±30.1, P＜0.05, n = 4) in melanoma cells after 6-h incubation with 4-HPR. The invasion through reconstituted basement membrane was also significantly reduced by 4-HPR treatment to 11.2±3.3 in SMMC 7721-k3 HCC (control 27±13.1), and to 24.3±3.2 in melanoma cells (control 67.5±10.1, P＜0.05, n = 3). Cell growth, especially in melanoma cells, was also significantly inhibited.Furthermore, 3 μmol/L of 4-HPR induced apoptosis in B16 melanoma cells (37.11±0.94%) more significantly than all-trans retinoic acid (P＜0.05), but it failed to induce apoptosis in SMMC 7721-k3 HCC. The mechanism for 4-HPR-induced apoptosis was not clear, but we observed that 4-HPR could regulate p27kip1, and overexpression of cerebroside sulfotransferase (CST) diminished the apoptosis induced by 4-HPR in melanoma cells.CONCLUSION: 4-HPR is a potent inhibitor of HCC migration and inducer of melanoma cell apoptosis. CST and p27kip1 expression might be associated with 4-HPR-induced apoptosis.展开更多
The non-classical HLA class Ⅰ antigen HLA-G is an immune modulator which inhibits the functions of T cells, NK cells, and the Dendritic cells （DC）. As a result, HLA-G expression in malignant cells may provide them ...The non-classical HLA class Ⅰ antigen HLA-G is an immune modulator which inhibits the functions of T cells, NK cells, and the Dendritic cells （DC）. As a result, HLA-G expression in malignant cells may provide them with a mechanism to escape the immune surveillance. In melanoma, HLA-G antigen expression has been found in 30% of surgically removed lesions but in less than 1% of established cell lines. One possible mechanism underlying the differential HLA-G expression in vivo and in vitro is that the HLA-G gene is epigenetically repressed in melanoma cells in vitro. To test this hypothesis, we treated the HLA-G negative melanoma cell line OCM-1A with the DNA methyltransferase inhibitor 5-aza-2＇-deoxycytidine （5-AC） and analyzed whether HLA-G expression can be restored. Our data strongly suggest that HLA-G is silenced as a result of CpG hypermethylation within a 5＇ regulatory region encompassing 220 bp upstream of the start codon. After treatment, HLA-G mRNA expression was dramatically increased. Western blot and flow cytometry showed that HLA-G protein was induced. Interestingly, HLA-G cell surface expression on the 5-AC treated OCM-1A cells is much less than that on the HLA-G positive JEG-3 cells while a similar amount of total HLA-G was observed. Possible mechanisms for the difference were analyzed in the study such as cell cold-treatment, peptide loading and antigen processing machinery components （APM） as well as β2 microglobulin （β2-m） expression. Data revealed that the APM component calreticulin might be involved in the lower HLA-G surface expression on OCM-1A cells. Taken together, our results indicated that DNA methylation is an important epigenetic mechanism by which HLA-G antigen expression is modulated in melanoma cells in vitro. Furthermore, to the first time, we hypothesized that the deficiency of calreticulin might be involved in the low HLA-G surface expression on the 5-AC treated OCM-1A cells.展开更多
Nestin is a class Ⅵ intermediate filament protein that was originally described as a neuronal stem cell marker during central nervous system (CNS) development, and is currently widely used in that capacity. Nestin is...Nestin is a class Ⅵ intermediate filament protein that was originally described as a neuronal stem cell marker during central nervous system (CNS) development, and is currently widely used in that capacity. Nestin is also expressed in non-neuronal immature or progenitor cells in normal tissues. Under pathological conditions, nestin is expressed in repair processes in the CNS, muscle, liver, and infarcted myocardium. Furthermore, increased nestin expression has been reported in various tumor cells, including CNS tumors, gastrointestinal stromal tumors, pancreatic cancer, prostate cancer, breast cancer, malignant melanoma, dermatofibrosarcoma protuberances, and thyroid tumors. Nestin is reported to correlate with aggressive growth, metastasis, and poor prognosis in some tumors; however, the roles of nestin in cancer cells have not been well characterized. Furthermore, nestin is more specifically expressed in proliferating small-sized tumor vessels in glioblastoma and gastric, colorectal, and prostate cancers than are other tumor vessel markers. These findings indicate that nestin may be a marker for newly synthesized tumor vessels and a therapeutic target for tumor angiogenesis. It has received a lot of attention recently as a cancer stem cell marker in various cancer cells including brain tumors, malignant rhabdoid tumors, and uterine, cervical, prostate, bladder, head and neck, ovarian, testicular, and pancreatic cancers. The purpose of this review is to clarify the roles of nestin in cancer cells and in tumor angiogenesis, and to examine the association between nestin and cancer stem cells. Nestin has the potential to serve as a molecular target for cancers with nestin-positive cancer cells and nestin-positive tumor vasculature.展开更多
基金Supported by the National Natural Science Foundation of China, No. 30070183 and 30470398
文摘AIM: To investigate the effect of N-(4-hydrophenyl) retinamide (4-HPR), the derivative of retinoic acid, on inhibition of migration, invasion, cell growth, and induction of apoptosis in hepatocellular carcinoma cells (HCCs) and malignant melanoma cells.METHODS: 4-HPR was chemically synthesized. Cellular migration and invasion were assayed by Borden chamber experiment. Cell growth was assayed by MTT chromometry.Apoptosis effect was measured using Hoechst 32258 staining and flow cytometry. Gene transfection was performed with lipofectamine.RESULTS: We observed that the migration of HCC and melanoma cells was significantly suppressed by 4-HPR and the migration cells were reduced to 58±5.03 (control 201±27.2, P＜0.05, n = 4) in SMMC 7721-k3 HCC, and to 254±25.04 (control 302±30.1, P＜0.05, n = 4) in melanoma cells after 6-h incubation with 4-HPR. The invasion through reconstituted basement membrane was also significantly reduced by 4-HPR treatment to 11.2±3.3 in SMMC 7721-k3 HCC (control 27±13.1), and to 24.3±3.2 in melanoma cells (control 67.5±10.1, P＜0.05, n = 3). Cell growth, especially in melanoma cells, was also significantly inhibited.Furthermore, 3 μmol/L of 4-HPR induced apoptosis in B16 melanoma cells (37.11±0.94%) more significantly than all-trans retinoic acid (P＜0.05), but it failed to induce apoptosis in SMMC 7721-k3 HCC. The mechanism for 4-HPR-induced apoptosis was not clear, but we observed that 4-HPR could regulate p27kip1, and overexpression of cerebroside sulfotransferase (CST) diminished the apoptosis induced by 4-HPR in melanoma cells.CONCLUSION: 4-HPR is a potent inhibitor of HCC migration and inducer of melanoma cell apoptosis. CST and p27kip1 expression might be associated with 4-HPR-induced apoptosis.
文摘The non-classical HLA class Ⅰ antigen HLA-G is an immune modulator which inhibits the functions of T cells, NK cells, and the Dendritic cells （DC）. As a result, HLA-G expression in malignant cells may provide them with a mechanism to escape the immune surveillance. In melanoma, HLA-G antigen expression has been found in 30% of surgically removed lesions but in less than 1% of established cell lines. One possible mechanism underlying the differential HLA-G expression in vivo and in vitro is that the HLA-G gene is epigenetically repressed in melanoma cells in vitro. To test this hypothesis, we treated the HLA-G negative melanoma cell line OCM-1A with the DNA methyltransferase inhibitor 5-aza-2＇-deoxycytidine （5-AC） and analyzed whether HLA-G expression can be restored. Our data strongly suggest that HLA-G is silenced as a result of CpG hypermethylation within a 5＇ regulatory region encompassing 220 bp upstream of the start codon. After treatment, HLA-G mRNA expression was dramatically increased. Western blot and flow cytometry showed that HLA-G protein was induced. Interestingly, HLA-G cell surface expression on the 5-AC treated OCM-1A cells is much less than that on the HLA-G positive JEG-3 cells while a similar amount of total HLA-G was observed. Possible mechanisms for the difference were analyzed in the study such as cell cold-treatment, peptide loading and antigen processing machinery components （APM） as well as β2 microglobulin （β2-m） expression. Data revealed that the APM component calreticulin might be involved in the lower HLA-G surface expression on OCM-1A cells. Taken together, our results indicated that DNA methylation is an important epigenetic mechanism by which HLA-G antigen expression is modulated in melanoma cells in vitro. Furthermore, to the first time, we hypothesized that the deficiency of calreticulin might be involved in the low HLA-G surface expression on the 5-AC treated OCM-1A cells.
基金Supported by Grants (No. S0801035, to Naito Z) from the Ministry of Education, Culture, Sports, Science, and Technol-ogy (MEXT), JapanGrant-in-Aid for Young Scientists (A, No. 22689038 to Matsuda Y)
文摘Nestin is a class Ⅵ intermediate filament protein that was originally described as a neuronal stem cell marker during central nervous system (CNS) development, and is currently widely used in that capacity. Nestin is also expressed in non-neuronal immature or progenitor cells in normal tissues. Under pathological conditions, nestin is expressed in repair processes in the CNS, muscle, liver, and infarcted myocardium. Furthermore, increased nestin expression has been reported in various tumor cells, including CNS tumors, gastrointestinal stromal tumors, pancreatic cancer, prostate cancer, breast cancer, malignant melanoma, dermatofibrosarcoma protuberances, and thyroid tumors. Nestin is reported to correlate with aggressive growth, metastasis, and poor prognosis in some tumors; however, the roles of nestin in cancer cells have not been well characterized. Furthermore, nestin is more specifically expressed in proliferating small-sized tumor vessels in glioblastoma and gastric, colorectal, and prostate cancers than are other tumor vessel markers. These findings indicate that nestin may be a marker for newly synthesized tumor vessels and a therapeutic target for tumor angiogenesis. It has received a lot of attention recently as a cancer stem cell marker in various cancer cells including brain tumors, malignant rhabdoid tumors, and uterine, cervical, prostate, bladder, head and neck, ovarian, testicular, and pancreatic cancers. The purpose of this review is to clarify the roles of nestin in cancer cells and in tumor angiogenesis, and to examine the association between nestin and cancer stem cells. Nestin has the potential to serve as a molecular target for cancers with nestin-positive cancer cells and nestin-positive tumor vasculature.
