calcitriol and Carcinoma--Hepatocellular

The combined antitumor effects of 1,25‑dihydroxy vitamin D3 [1,25(OH)2D3] and the Notch inhibitor N‑[N‑-(3,5‑difluorophenacetyl)‑L‑alanyl]‑S‑phenylglycine t‑butyl ester (DAPT, a synthetic γ secretase inhibitor) in liver cancer cells remain to be fully elucidated. In the present study, HepG2 cells were divided into six groups and different treatments were applied: Control, 10‑10 M 1,25(OH)2D3, 10‑8 M 1,25(OH)2D3, 10‑6 M 1,25(OH)2D3, 1 µM DAPT, 5 µM DAPT, 10 µM DAPT, and 10‑6 M 1,25(OH)2D3 + 10 µM DAPT. The proliferation, cell cycle, apoptosis, migration and invasion of the cells were then examined. The expression levels of Notch and its ligand Jagged were detected by reverse transcription‑quantitative polymerase chain reaction and western blot analyses. The results revealed that 1,25(OH)2D3 inhibited cell proliferation, migration and invasion; arrested cell cycle at the G1 phase, and promoted apoptosis in a concentration‑dependent manner between 10‑10 and 10‑6 M. DAPT inhibited cell proliferation, migration and invasion, arrested cell cycle at the G1 phase, and promoted apoptosis in a concentration‑dependent manner between 1 and 10 µM. Additionally, 1,25(OH)2D3 and/or DAPT reduced the expression of Notch1, Notch2, Jagged1 and Jagged2. The co‑application of 10 µM DAPT further increased the anticancer effect of 10‑6 M 1,25(OH)2D3. Collectively, these results indicated that the treatment of HepG2 cells with 1,25(OH)2D3 inactivated Notch signaling, prevented proliferation, migration and invasion, and promoted apoptosis. The combined application of 1,25(OH)2D3 with DAPT may be a useful treatment for preventing the onset or progression of liver cancer.

Topics: Apoptosis; Biomarkers, Tumor; Carcinoma, Hepatocellular; Cell Movement; Cell Proliferation; Diamines; Drug Combinations; Humans; Liver Neoplasms; Neoplasm Invasiveness; Receptors, Notch; Thiazoles; Tumor Cells, Cultured; Vitamin D

Hepatic progenitor cells (HPCs) might be the origin of hepatocellular carcinoma. 1α,25-Dihydroxyvitamin D3 (1,25(OH)

Topics: Acyltransferases; Adaptor Proteins, Signal Transducing; Aflatoxin B1; Animals; Apoptosis; Carcinoma, Hepatocellular; Cell Dedifferentiation; Cell Proliferation; Female; Gene Expression Regulation, Neoplastic; Hepatocytes; Humans; Liver Neoplasms; Mice; Mice, Inbred ICR; Phosphatidylinositol 3-Kinases; Phosphoproteins; Poisons; Proto-Oncogene Proteins c-akt; Stem Cells; Transcription Factors; Tumor Cells, Cultured; Vitamin D; Xenograft Model Antitumor Assays; YAP-Signaling Proteins

Hepatocellular carcinoma (HCC) is the most diagnosed liver cancer without effective treatments available for advanced HCC. Vitamin D is getting popular due to its anti-cancer characteristics. However, the clinical application of 1α,25(OH)2D, the active form of vitamin, is hampered by its hypercalcemia side effect. 1α,25(OH)2D is converted from 25(OH)D, the index of serum vitamin D status, by CYP27B1, which is originally found in kidneys but recently detected in non-renal tissues. 25(OH)D has been shown to repress some cancers expressing CYP27B1 due to the local conversion of 25(OH)D to 1α,25(OH)2D, which works in a intra-, auto-, or paracrine manner and thus minimizes the risk of hypercalcemia. In this study, we found CYP27B1 expression in human hepatocyte, HCC, and HepG2 cells. As we treated HepG2 cells with 25(OH)D, the 1α,25(OH)2D target gene CYP24A1 expression was increased and was further upregulated as CYP27B1 transfection or downregulated as CYP27B1 knockdown. Other 1α,25(OH)2D target genes in HepG2 cells, p21 and p27 were also stimulated by 25(OH)D after CYP27B1 transfection. Further, 25(OH)D could inhibit HepG2 cells growth, which was potentiated by CYP27B1 transfection. Collectively, we showed for the first time that HCC expressed CYP27B1 and was able to covert 25(OH)D to 1α,25(OH)2D in vitro, thus responsive to 25(OH)D treatment. Our data justifies the application of 25(OH)D and CYP27B1 gene transfection therapy in further HCC treatment studies.

Topics: 25-Hydroxyvitamin D3 1-alpha-Hydroxylase; Carcinoma, Hepatocellular; Cell Proliferation; Hep G2 Cells; Humans; Liver Neoplasms; Vitamin D

All-trans retinoic acid (ATRA) and 1,25-dihydroxy vitamin D3 [1,25(OH)2D3] can inhibit the proliferation of tumor cells and induce their differentiation. They have been used to treat leukemia, but their effects on solid tumors remain unclear. This study was to investigate the effects of ATRA and 1,25(OH)2D3 on growth and cell cycle of human hepatoma cell line HepG2, and explore the molecular mechanism.. After HepG2 cells were treated with ATRA, 1,25(OH)2D3, or the combination of both chemicals, cell survival was assessed by MTT assay, morphologic changes were observed under light microscope, cell cycle and apoptosis were determined by flow cytometry (FCM) with dual staining of AnnexinV/PI, and the expression of p21(WAF/CIP1) and p27(KIP1) mRNA and protein were determined by reverse transcription-polymerase chain reaction (RT-PCR) and FCM.. ATRA and 1,25(OH)2D3, used alone or in combination, inhibited the growth of HepG2 cells in a time- and dose-dependent manner. The inhibition was more obvious in the combination group than in ATRA group and 1,25(OH)2D3 group (P<0.05). FCM analysis indicated that 10 nmol/L 1,25(OH)2D3, used alone or in combination with ATRA for 72 h, strongly induced G1 phase arrest of HepG2 cells [(54.27+/-3.69)% and (65.64+/-5.65)% vs. (40.40+/-1.91)% of the control, P<0.05], but 1 micromol/L ATRA did not show obvious effect. All of them induced apoptosis (P<0.05). The mRNA level of p21(WAF/CIP1) was enhanced by 35% and 56% of control in the cells treated with 10 nmol/L 1,25(OH)2D3 or 1,25(OH)2D3 combined with ATRA for 24 h. The combination of 1,25(OH)2D3 and ATRA markedly enhanced the protein levels of p21(WAF/CIP1) and p27(KIP1) as compared with 1,25(OH)2D3 alone, and 1 micromol/L ATRA did not enhance the protein levels of p21(WAF/CIP1) and p27(KIP1) in HepG2 cells.. ATRA and 1,25(OH)2D3 could inhibit growth and induce apoptosis of HepG2 cells, and the molecular basis of the cell cycle blockade by 1,25(OH)2D3 may be associated with the up-regulation of CDK inhibitors p21(WAF/CIP1) and p27(KIP1), which mediate G1 arrest. Furthermore, the combination of ATRA and 1,25(OH)2D3 can exert synergistic inhibitory effect on the growth of HepG2 cells.

Topics: Antineoplastic Agents; Apoptosis; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Proliferation; Cyclin-Dependent Kinase Inhibitor p21; Cyclin-Dependent Kinase Inhibitor p27; Drug Synergism; G1 Phase; Gene Expression Regulation, Neoplastic; Humans; Intracellular Signaling Peptides and Proteins; RNA, Messenger; Tretinoin; Up-Regulation; Vitamin D